A fish out of water: unique observations of water in planet-forming disks

INVITATION
PhD de ense
Ma go Leemke
F eezing condi ions
in wa m disks
snowlines and hei e ec
on he chemical s uc u e
o plane - o ming disks
Wednesday
14 Feb ua y 2024
10:00
Academiegebouw
Uni e si ei Leiden
Rapenbu g 73
Ma go Leemke
F eezing condi ions in wa m disks
F eezing condi ions in wa m disks Ma go Leemke
snowlines and hei e ec on he chemical
s uc u e o plane - o ming disks
snowlines and hei e ec on he chemical s uc u e o plane - o ming disks
Fi s de ec ion o D2O in a disk:
Is wa e inhe i ed o ep ocessed?
M. Leemke , J. J. Tobin, S. Facchini, P. Cu one,
A. S. Boo h, K. Fu uya, and M. L. R. an ’ Ho ERC UNVEIL: 101076613
• S eaming ins abili y a ound snowline (e.g., D ażkowska e al. 2017, Schoonenbe g e al. 2017)
• Aid g ain g ow h (Blum e al. 2008, Okuzumi e al. 2012)
• Majo ca ie o oxygen
• Good sol en
Nes o ny e al. 2019
S eaming ins abili y
Wa e (ice) is key o plane o ma ion
gas
H
α
wa e
snowline
~ 1 au
Rese oi 1:
he mally deso bed
wa e
gas
H
α
gas
H
α
Rese oi 2:
pho odeso bed
wa e
Rese oi 3:
e o med wa e
3 ese oi s o wa e
Obse a ions o wa e in disks
Spi ze
gas
H
α
A&A 648, A24 (2021)
0
50
100
150
200
z(au)
a) log n(H2)(cm3)
4
5
6
7
8
9
0
50
100
150
200
z(au)
b) T(K)
20
40
60
80
100
120
140
160
180
200
0 100 200 300
R(au)
0
50
100
150
200
z(au)
c) log X(H2O)
132
50
100
12
11
10
9
8
7
6
5
4
Fig. 27. C oss sec ion o one quad an o a model o a He big disk,
ailo ed o ha a ound HD 100546. (a)H
2numbe densi y, (b) gas
empe a u e ( aken equal o he dus empe a u e), and (c) calcula ed
H2O abundance. Fu he de ails o he model can be ound in he ex
and e e ences. The H2O abundance can be di ided in h ee egions as
indica ed (see also Fig. 25).
20 0 20
-sou ce (km s1)
0
25
50
75
100
125
150
TMB (mK)
H2O110-101
TW Hya
HD100546
HD163296
AA Tau + MWC480
+ LkCa15 + DM Tau
x5
20 0 20
-sou ce (km s1)
H2O111 000
TW Hya
HD100546
HD163296
Fig. 28. O e iew o de ec ed emission o H2O110–101 (le ) and
111–000 ( igh ) wi h He schel-HIFI o TW Hya, HD 100456, HD 163296
and he s acked esul s o AA Tau, MWC 480, LkCa 15, and DM Tau.
Da a om Hoge heijde e al. (2011); Du e al. (2017), He schel a chi e
and Hoge heijde e al. (p i . comm.).
in eg a ion imes ( ypically >10 h) and hus lowes noise le els.
Fo all o he sou ces, obse ed o a ious ms le els, only uppe
limi s we e ob ained. Figu e 29 shows he de ec ions and uppe
Fig. 29. Line luminosi ies o models and obse a ions o o ho-H2O
110–101 o plane - o ming disks obse ed wi h He schel-HIFI. Solid
blue and ed lines show p edic ed line luminosi ies o a He big disk
model (blue) and a T Tau i disk model ( ed); see ex o de ails.
No e he loga i hmic scale. The e ec s o non-uni y illing ac o s a e
illus a ed by shaded lines a 50 and 25%. The obse a ional da a a e
om Hoge heijde e al. (2011); Du e al. (2017) and Hoge heijde e al.
(p i . comm.). Filled ci cles show de ec ions, blue o he He big s a
HD 100546 and ed o he T Tau i s a TW Hya. The g ay ci cles
connec ed by he solid g ay line show he de ec ed line luminosi y o
he s acked de ec ion o AA Tau, LkCa15, MWC 480 and DM Tau.
Down-poin ing iangles show uppe limi s (blue: He big disks; ed:
T Tau i disks). Da a a e plo ed e sus he obse ed size o he disk as
measu ed h ough CO emission (uppe panel) and mm-wa eleng h con-
inuum emission (lowe panel); o he s acked de ec ion (g ay line) he
ange o disk sizes is plo ed. Obse ed disk sizes a e aken om Walsh
e al. (2014); And ews e al. (2012); Loomis e al. (2017); Be gin e al.
(2016); Kudo e al. (2018); Jin e al. (2019); Qi e al. (2003); Liu e al.
(2019); Fedele e al. (2017); Huang e al. (2016); Du ey e al. (2003,
2016); Hughes e al. (2009); Macías e al. (2018); Isella e al. (2016);
Boehle e al. (2018); Huélamo e al. (2015); Clee es e al. (2016).
Line luminosi ies and disk sizes a e scaled o he la es Gaia dis ance
es ima es.
limi s in e ms o eloci y-in eg a ed line luminosi ies, using he
mos up- o-da e dis ances o he sou ces ob ained om Gaia.
Figu e 29 plo s he obse ed line luminosi ies and he uppe
limi s as unc ion o he gas and dus ou e adii o he disk
as measu ed in 12CO emission and h ough he mm-con inuum
emission. I also compa es he obse a ions o he expec ed
emission o a “ ypical” T Tau i disk ( ed) and a “ ypical”
He big Ae disk (blue). Fo he T Tau i disk, he TW Hya model
o Hoge heijde e al. (2011) and Salinas e al. (2016) is used: a
disk mass o 0.04 M, disk ou e adius o 200 au, and a disk
inclina ion o 7. Fo he He big disk, a model o he HD 100546
disk is adop ed (Hoge heijde e al., p i . comm.): a disk mass
o 0.01 M, a disk ou e adius o 400au, and a disk inclina-
ion o 42. In bo h cases, he disk empe a u e is calcula ed
A24, page 30 o 57
e.g., Ca e al. 2004, 2008, 2011, Sally e al. 2008, 2011, 2015, Hoge heijde e al. 2011, Salinas e al. 2016, Du e al. 2017, an Dishoeck e al. 2021
• Cold wa e : a ely de ec ed
• Deple ed ese oi o ices
• Un esol ed compac / ing-shaped H2O emission
A&A 648, A24 (2021)
0
50
100
150
200
z(au)
a) log n(H2)(cm3)
4
5
6
7
8
9
0
50
100
150
200
z(au)
b) T(K)
20
40
60
80
100
120
140
160
180
200
0 100 200 300
R(au)
0
50
100
150
200
z(au)
c) log X(H2O)
132
50
100
12
11
10
9
8
7
6
5
4
Fig. 27. C oss sec ion o one quad an o a model o a He big disk,
ailo ed o ha a ound HD 100546. (a)H
2numbe densi y, (b) gas
empe a u e ( aken equal o he dus empe a u e), and (c) calcula ed
H2O abundance. Fu he de ails o he model can be ound in he ex
and e e ences. The H2O abundance can be di ided in h ee egions as
indica ed (see also Fig. 25).
20 0 20
-sou ce (km s1)
0
25
50
75
100
125
150
TMB (mK)
H2O110-101
TW Hya
HD100546
HD163296
AA Tau + MWC480
+ LkCa15 + DM Tau
x5
20 0 20
-sou ce (km s1)
H2O111 000
TW Hya
HD100546
HD163296
Fig. 28. O e iew o de ec ed emission o H2O110–101 (le ) and
111–000 ( igh ) wi h He schel-HIFI o TW Hya, HD 100456, HD 163296
and he s acked esul s o AA Tau, MWC 480, LkCa 15, and DM Tau.
Da a om Hoge heijde e al. (2011); Du e al. (2017), He schel a chi e
and Hoge heijde e al. (p i . comm.).
in eg a ion imes ( ypically >10 h) and hus lowes noise le els.
Fo all o he sou ces, obse ed o a ious ms le els, only uppe
limi s we e ob ained. Figu e 29 shows he de ec ions and uppe
Fig. 29. Line luminosi ies o models and obse a ions o o ho-H2O
110–101 o plane - o ming disks obse ed wi h He schel-HIFI. Solid
blue and ed lines show p edic ed line luminosi ies o a He big disk
model (blue) and a T Tau i disk model ( ed); see ex o de ails.
No e he loga i hmic scale. The e ec s o non-uni y illing ac o s a e
illus a ed by shaded lines a 50 and 25%. The obse a ional da a a e
om Hoge heijde e al. (2011); Du e al. (2017) and Hoge heijde e al.
(p i . comm.). Filled ci cles show de ec ions, blue o he He big s a
HD 100546 and ed o he T Tau i s a TW Hya. The g ay ci cles
connec ed by he solid g ay line show he de ec ed line luminosi y o
he s acked de ec ion o AA Tau, LkCa15, MWC 480 and DM Tau.
Down-poin ing iangles show uppe limi s (blue: He big disks; ed:
T Tau i disks). Da a a e plo ed e sus he obse ed size o he disk as
measu ed h ough CO emission (uppe panel) and mm-wa eleng h con-
inuum emission (lowe panel); o he s acked de ec ion (g ay line) he
ange o disk sizes is plo ed. Obse ed disk sizes a e aken om Walsh
e al. (2014); And ews e al. (2012); Loomis e al. (2017); Be gin e al.
(2016); Kudo e al. (2018); Jin e al. (2019); Qi e al. (2003); Liu e al.
(2019); Fedele e al. (2017); Huang e al. (2016); Du ey e al. (2003,
2016); Hughes e al. (2009); Macías e al. (2018); Isella e al. (2016);
Boehle e al. (2018); Huélamo e al. (2015); Clee es e al. (2016).
Line luminosi ies and disk sizes a e scaled o he la es Gaia dis ance
es ima es.
limi s in e ms o eloci y-in eg a ed line luminosi ies, using he
mos up- o-da e dis ances o he sou ces ob ained om Gaia.
Figu e 29 plo s he obse ed line luminosi ies and he uppe
limi s as unc ion o he gas and dus ou e adii o he disk
as measu ed in 12CO emission and h ough he mm-con inuum
emission. I also compa es he obse a ions o he expec ed
emission o a “ ypical” T Tau i disk ( ed) and a “ ypical”
He big Ae disk (blue). Fo he T Tau i disk, he TW Hya model
o Hoge heijde e al. (2011) and Salinas e al. (2016) is used: a
disk mass o 0.04 M, disk ou e adius o 200 au, and a disk
inclina ion o 7. Fo he He big disk, a model o he HD 100546
disk is adop ed (Hoge heijde e al., p i . comm.): a disk mass
o 0.01 M, a disk ou e adius o 400au, and a disk inclina-
ion o 42. In bo h cases, he disk empe a u e is calcula ed
A24, page 30 o 57
A&A 648, A24 (2021)
0
50
100
150
200
z(au)
a) log n(H2)(cm3)
4
5
6
7
8
9
0
50
100
150
200
z(au)
b) T(K)
20
40
60
80
100
120
140
160
180
200
0 100 200 300
R(au)
0
50
100
150
200
z(au)
c) log X(H2O)
132
50
100
12
11
10
9
8
7
6
5
4
Fig. 27. C oss sec ion o one quad an o a model o a He big disk,
ailo ed o ha a ound HD 100546. (a)H
2numbe densi y, (b) gas
empe a u e ( aken equal o he dus empe a u e), and (c) calcula ed
H2O abundance. Fu he de ails o he model can be ound in he ex
and e e ences. The H2O abundance can be di ided in h ee egions as
indica ed (see also Fig. 25).
20 0 20
-sou ce (km s1)
0
25
50
75
100
125
150
TMB (mK)
H2O110-101
TW Hya
HD100546
HD163296
AA Tau + MWC480
+ LkCa15 + DM Tau
x5
20 0 20
-sou ce (km s1)
H2O111 000
TW Hya
HD100546
HD163296
Fig. 28. O e iew o de ec ed emission o H2O110–101 (le ) and
111–000 ( igh ) wi h He schel-HIFI o TW Hya, HD 100456, HD 163296
and he s acked esul s o AA Tau, MWC 480, LkCa 15, and DM Tau.
Da a om Hoge heijde e al. (2011); Du e al. (2017), He schel a chi e
and Hoge heijde e al. (p i . comm.).
in eg a ion imes ( ypically >10 h) and hus lowes noise le els.
Fo all o he sou ces, obse ed o a ious ms le els, only uppe
limi s we e ob ained. Figu e 29 shows he de ec ions and uppe
Fig. 29. Line luminosi ies o models and obse a ions o o ho-H2O
110–101 o plane - o ming disks obse ed wi h He schel-HIFI. Solid
blue and ed lines show p edic ed line luminosi ies o a He big disk
model (blue) and a T Tau i disk model ( ed); see ex o de ails.
No e he loga i hmic scale. The e ec s o non-uni y illing ac o s a e
illus a ed by shaded lines a 50 and 25%. The obse a ional da a a e
om Hoge heijde e al. (2011); Du e al. (2017) and Hoge heijde e al.
(p i . comm.). Filled ci cles show de ec ions, blue o he He big s a
HD 100546 and ed o he T Tau i s a TW Hya. The g ay ci cles
connec ed by he solid g ay line show he de ec ed line luminosi y o
he s acked de ec ion o AA Tau, LkCa15, MWC 480 and DM Tau.
Down-poin ing iangles show uppe limi s (blue: He big disks; ed:
T Tau i disks). Da a a e plo ed e sus he obse ed size o he disk as
measu ed h ough CO emission (uppe panel) and mm-wa eleng h con-
inuum emission (lowe panel); o he s acked de ec ion (g ay line) he
ange o disk sizes is plo ed. Obse ed disk sizes a e aken om Walsh
e al. (2014); And ews e al. (2012); Loomis e al. (2017); Be gin e al.
(2016); Kudo e al. (2018); Jin e al. (2019); Qi e al. (2003); Liu e al.
(2019); Fedele e al. (2017); Huang e al. (2016); Du ey e al. (2003,
2016); Hughes e al. (2009); Macías e al. (2018); Isella e al. (2016);
Boehle e al. (2018); Huélamo e al. (2015); Clee es e al. (2016).
Line luminosi ies and disk sizes a e scaled o he la es Gaia dis ance
es ima es.
limi s in e ms o eloci y-in eg a ed line luminosi ies, using he
mos up- o-da e dis ances o he sou ces ob ained om Gaia.
Figu e 29 plo s he obse ed line luminosi ies and he uppe
limi s as unc ion o he gas and dus ou e adii o he disk
as measu ed in 12CO emission and h ough he mm-con inuum
emission. I also compa es he obse a ions o he expec ed
emission o a “ ypical” T Tau i disk ( ed) and a “ ypical”
He big Ae disk (blue). Fo he T Tau i disk, he TW Hya model
o Hoge heijde e al. (2011) and Salinas e al. (2016) is used: a
disk mass o 0.04 M, disk ou e adius o 200 au, and a disk
inclina ion o 7. Fo he He big disk, a model o he HD 100546
disk is adop ed (Hoge heijde e al., p i . comm.): a disk mass
o 0.01 M, a disk ou e adius o 400au, and a disk inclina-
ion o 42. In bo h cases, he disk empe a u e is calcula ed
A24, page 30 o 57
A&A 648, A24 (2021)
0
50
100
150
200
z(au)
a) log n(H2)(cm3)
4
5
6
7
8
9
0
50
100
150
200
z(au)
b) T(K)
20
40
60
80
100
120
140
160
180
200
0 100 200 300
R(au)
0
50
100
150
200
z(au)
c) log X(H2O)
132
50
100
12
11
10
9
8
7
6
5
4
Fig. 27. C oss sec ion o one quad an o a model o a He big disk,
ailo ed o ha a ound HD 100546. (a)H
2numbe densi y, (b) gas
empe a u e ( aken equal o he dus empe a u e), and (c) calcula ed
H2O abundance. Fu he de ails o he model can be ound in he ex
and e e ences. The H2O abundance can be di ided in h ee egions as
indica ed (see also Fig. 25).
20 0 20
-sou ce (km s1)
0
25
50
75
100
125
150
TMB (mK)
H2O110-101
TW Hya
HD100546
HD163296
AA Tau + MWC480
+ LkCa15 + DM Tau
x5
20 0 20
-sou ce (km s1)
H2O111 000
TW Hya
HD100546
HD163296
Fig. 28. O e iew o de ec ed emission o H2O110–101 (le ) and
111–000 ( igh ) wi h He schel-HIFI o TW Hya, HD 100456, HD 163296
and he s acked esul s o AA Tau, MWC 480, LkCa 15, and DM Tau.
Da a om Hoge heijde e al. (2011); Du e al. (2017), He schel a chi e
and Hoge heijde e al. (p i . comm.).
in eg a ion imes ( ypically >10 h) and hus lowes noise le els.
Fo all o he sou ces, obse ed o a ious ms le els, only uppe
limi s we e ob ained. Figu e 29 shows he de ec ions and uppe
Fig. 29. Line luminosi ies o models and obse a ions o o ho-H2O
110–101 o plane - o ming disks obse ed wi h He schel-HIFI. Solid
blue and ed lines show p edic ed line luminosi ies o a He big disk
model (blue) and a T Tau i disk model ( ed); see ex o de ails.
No e he loga i hmic scale. The e ec s o non-uni y illing ac o s a e
illus a ed by shaded lines a 50 and 25%. The obse a ional da a a e
om Hoge heijde e al. (2011); Du e al. (2017) and Hoge heijde e al.
(p i . comm.). Filled ci cles show de ec ions, blue o he He big s a
HD 100546 and ed o he T Tau i s a TW Hya. The g ay ci cles
connec ed by he solid g ay line show he de ec ed line luminosi y o
he s acked de ec ion o AA Tau, LkCa15, MWC 480 and DM Tau.
Down-poin ing iangles show uppe limi s (blue: He big disks; ed:
T Tau i disks). Da a a e plo ed e sus he obse ed size o he disk as
measu ed h ough CO emission (uppe panel) and mm-wa eleng h con-
inuum emission (lowe panel); o he s acked de ec ion (g ay line) he
ange o disk sizes is plo ed. Obse ed disk sizes a e aken om Walsh
e al. (2014); And ews e al. (2012); Loomis e al. (2017); Be gin e al.
(2016); Kudo e al. (2018); Jin e al. (2019); Qi e al. (2003); Liu e al.
(2019); Fedele e al. (2017); Huang e al. (2016); Du ey e al. (2003,
2016); Hughes e al. (2009); Macías e al. (2018); Isella e al. (2016);
Boehle e al. (2018); Huélamo e al. (2015); Clee es e al. (2016).
Line luminosi ies and disk sizes a e scaled o he la es Gaia dis ance
es ima es.
limi s in e ms o eloci y-in eg a ed line luminosi ies, using he
mos up- o-da e dis ances o he sou ces ob ained om Gaia.
Figu e 29 plo s he obse ed line luminosi ies and he uppe
limi s as unc ion o he gas and dus ou e adii o he disk
as measu ed in 12CO emission and h ough he mm-con inuum
emission. I also compa es he obse a ions o he expec ed
emission o a “ ypical” T Tau i disk ( ed) and a “ ypical”
He big Ae disk (blue). Fo he T Tau i disk, he TW Hya model
o Hoge heijde e al. (2011) and Salinas e al. (2016) is used: a
disk mass o 0.04 M, disk ou e adius o 200 au, and a disk
inclina ion o 7. Fo he He big disk, a model o he HD 100546
disk is adop ed (Hoge heijde e al., p i . comm.): a disk mass
o 0.01 M, a disk ou e adius o 400au, and a disk inclina-
ion o 42. In bo h cases, he disk empe a u e is calcula ed
A24, page 30 o 57
A&A 648, A24 (2021)
0
50
100
150
200
z(au)
a) log n(H2)(cm3)
4
5
6
7
8
9
0
50
100
150
200
z(au)
b) T(K)
20
40
60
80
100
120
140
160
180
200
0 100 200 300
R(au)
0
50
100
150
200
z(au)
c) log X(H2O)
132
50
100
12
11
10
9
8
7
6
5
4
Fig. 27. C oss sec ion o one quad an o a model o a He big disk,
ailo ed o ha a ound HD 100546. (a)H
2numbe densi y, (b) gas
empe a u e ( aken equal o he dus empe a u e), and (c) calcula ed
H2O abundance. Fu he de ails o he model can be ound in he ex
and e e ences. The H2O abundance can be di ided in h ee egions as
indica ed (see also Fig. 25).
20 0 20
-sou ce (km s1)
0
25
50
75
100
125
150
TMB (mK)
H2O110-101
TW Hya
HD100546
HD163296
AA Tau + MWC480
+ LkCa15 + DM Tau
x5
20 0 20
-sou ce (km s1)
H2O111 000
TW Hya
HD100546
HD163296
Fig. 28. O e iew o de ec ed emission o H2O110–101 (le ) and
111–000 ( igh ) wi h He schel-HIFI o TW Hya, HD 100456, HD 163296
and he s acked esul s o AA Tau, MWC 480, LkCa 15, and DM Tau.
Da a om Hoge heijde e al. (2011); Du e al. (2017), He schel a chi e
and Hoge heijde e al. (p i . comm.).
in eg a ion imes ( ypically >10 h) and hus lowes noise le els.
Fo all o he sou ces, obse ed o a ious ms le els, only uppe
limi s we e ob ained. Figu e 29 shows he de ec ions and uppe
Fig. 29. Line luminosi ies o models and obse a ions o o ho-H2O
110–101 o plane - o ming disks obse ed wi h He schel-HIFI. Solid
blue and ed lines show p edic ed line luminosi ies o a He big disk
model (blue) and a T Tau i disk model ( ed); see ex o de ails.
No e he loga i hmic scale. The e ec s o non-uni y illing ac o s a e
illus a ed by shaded lines a 50 and 25%. The obse a ional da a a e
om Hoge heijde e al. (2011); Du e al. (2017) and Hoge heijde e al.
(p i . comm.). Filled ci cles show de ec ions, blue o he He big s a
HD 100546 and ed o he T Tau i s a TW Hya. The g ay ci cles
connec ed by he solid g ay line show he de ec ed line luminosi y o
he s acked de ec ion o AA Tau, LkCa15, MWC 480 and DM Tau.
Down-poin ing iangles show uppe limi s (blue: He big disks; ed:
T Tau i disks). Da a a e plo ed e sus he obse ed size o he disk as
measu ed h ough CO emission (uppe panel) and mm-wa eleng h con-
inuum emission (lowe panel); o he s acked de ec ion (g ay line) he
ange o disk sizes is plo ed. Obse ed disk sizes a e aken om Walsh
e al. (2014); And ews e al. (2012); Loomis e al. (2017); Be gin e al.
(2016); Kudo e al. (2018); Jin e al. (2019); Qi e al. (2003); Liu e al.
(2019); Fedele e al. (2017); Huang e al. (2016); Du ey e al. (2003,
2016); Hughes e al. (2009); Macías e al. (2018); Isella e al. (2016);
Boehle e al. (2018); Huélamo e al. (2015); Clee es e al. (2016).
Line luminosi ies and disk sizes a e scaled o he la es Gaia dis ance
es ima es.
limi s in e ms o eloci y-in eg a ed line luminosi ies, using he
mos up- o-da e dis ances o he sou ces ob ained om Gaia.
Figu e 29 plo s he obse ed line luminosi ies and he uppe
limi s as unc ion o he gas and dus ou e adii o he disk
as measu ed in 12CO emission and h ough he mm-con inuum
emission. I also compa es he obse a ions o he expec ed
emission o a “ ypical” T Tau i disk ( ed) and a “ ypical”
He big Ae disk (blue). Fo he T Tau i disk, he TW Hya model
o Hoge heijde e al. (2011) and Salinas e al. (2016) is used: a
disk mass o 0.04 M, disk ou e adius o 200 au, and a disk
inclina ion o 7. Fo he He big disk, a model o he HD 100546
disk is adop ed (Hoge heijde e al., p i . comm.): a disk mass
o 0.01 M, a disk ou e adius o 400au, and a disk inclina-
ion o 42. In bo h cases, he disk empe a u e is calcula ed
A24, page 30 o 57
A&A 648, A24 (2021)
0
50
100
150
200
z(au)
a) log n(H2)(cm3)
4
5
6
7
8
9
0
50
100
150
200
z(au)
b) T(K)
20
40
60
80
100
120
140
160
180
200
0 100 200 300
R(au)
0
50
100
150
200
z(au)
c) log X(H2O)
132
50
100
12
11
10
9
8
7
6
5
4
Fig. 27. C oss sec ion o one quad an o a model o a He big disk,
ailo ed o ha a ound HD 100546. (a)H
2numbe densi y, (b) gas
empe a u e ( aken equal o he dus empe a u e), and (c) calcula ed
H2O abundance. Fu he de ails o he model can be ound in he ex
and e e ences. The H2O abundance can be di ided in h ee egions as
indica ed (see also Fig. 25).
20 0 20
-sou ce (km s1)
0
25
50
75
100
125
150
TMB (mK)
H2O110-101
TW Hya
HD100546
HD163296
AA Tau + MWC480
+ LkCa15 + DM Tau
x5
20 0 20
-sou ce (km s1)
H2O111 000
TW Hya
HD100546
HD163296
Fig. 28. O e iew o de ec ed emission o H2O110–101 (le ) and
111–000 ( igh ) wi h He schel-HIFI o TW Hya, HD 100456, HD 163296
and he s acked esul s o AA Tau, MWC 480, LkCa 15, and DM Tau.
Da a om Hoge heijde e al. (2011); Du e al. (2017), He schel a chi e
and Hoge heijde e al. (p i . comm.).
in eg a ion imes ( ypically >10 h) and hus lowes noise le els.
Fo all o he sou ces, obse ed o a ious ms le els, only uppe
limi s we e ob ained. Figu e 29 shows he de ec ions and uppe
Fig. 29. Line luminosi ies o models and obse a ions o o ho-H2O
110–101 o plane - o ming disks obse ed wi h He schel-HIFI. Solid
blue and ed lines show p edic ed line luminosi ies o a He big disk
model (blue) and a T Tau i disk model ( ed); see ex o de ails.
No e he loga i hmic scale. The e ec s o non-uni y illing ac o s a e
illus a ed by shaded lines a 50 and 25%. The obse a ional da a a e
om Hoge heijde e al. (2011); Du e al. (2017) and Hoge heijde e al.
(p i . comm.). Filled ci cles show de ec ions, blue o he He big s a
HD 100546 and ed o he T Tau i s a TW Hya. The g ay ci cles
connec ed by he solid g ay line show he de ec ed line luminosi y o
he s acked de ec ion o AA Tau, LkCa15, MWC 480 and DM Tau.
Down-poin ing iangles show uppe limi s (blue: He big disks; ed:
T Tau i disks). Da a a e plo ed e sus he obse ed size o he disk as
measu ed h ough CO emission (uppe panel) and mm-wa eleng h con-
inuum emission (lowe panel); o he s acked de ec ion (g ay line) he
ange o disk sizes is plo ed. Obse ed disk sizes a e aken om Walsh
e al. (2014); And ews e al. (2012); Loomis e al. (2017); Be gin e al.
(2016); Kudo e al. (2018); Jin e al. (2019); Qi e al. (2003); Liu e al.
(2019); Fedele e al. (2017); Huang e al. (2016); Du ey e al. (2003,
2016); Hughes e al. (2009); Macías e al. (2018); Isella e al. (2016);
Boehle e al. (2018); Huélamo e al. (2015); Clee es e al. (2016).
Line luminosi ies and disk sizes a e scaled o he la es Gaia dis ance
es ima es.
limi s in e ms o eloci y-in eg a ed line luminosi ies, using he
mos up- o-da e dis ances o he sou ces ob ained om Gaia.
Figu e 29 plo s he obse ed line luminosi ies and he uppe
limi s as unc ion o he gas and dus ou e adii o he disk
as measu ed in 12CO emission and h ough he mm-con inuum
emission. I also compa es he obse a ions o he expec ed
emission o a “ ypical” T Tau i disk ( ed) and a “ ypical”
He big Ae disk (blue). Fo he T Tau i disk, he TW Hya model
o Hoge heijde e al. (2011) and Salinas e al. (2016) is used: a
disk mass o 0.04 M, disk ou e adius o 200 au, and a disk
inclina ion o 7. Fo he He big disk, a model o he HD 100546
disk is adop ed (Hoge heijde e al., p i . comm.): a disk mass
o 0.01 M, a disk ou e adius o 400au, and a disk inclina-
ion o 42. In bo h cases, he disk empe a u e is calcula ed
A24, page 30 o 57
A&A 648, A24 (2021)
0
50
100
150
200
z(au)
a) log n(H2)(cm3)
4
5
6
7
8
9
0
50
100
150
200
z(au)
b) T(K)
20
40
60
80
100
120
140
160
180
200
0 100 200 300
R(au)
0
50
100
150
200
z(au)
c) log X(H2O)
132
50
100
12
11
10
9
8
7
6
5
4
Fig. 27. C oss sec ion o one quad an o a model o a He big disk,
ailo ed o ha a ound HD 100546. (a)H
2numbe densi y, (b) gas
empe a u e ( aken equal o he dus empe a u e), and (c) calcula ed
H2O abundance. Fu he de ails o he model can be ound in he ex
and e e ences. The H2O abundance can be di ided in h ee egions as
indica ed (see also Fig. 25).
20 0 20
-sou ce (km s1)
0
25
50
75
100
125
150
TMB (mK)
H2O110-101
TW Hya
HD100546
HD163296
AA Tau + MWC480
+ LkCa15 + DM Tau
x5
20 0 20
-sou ce (km s1)
H2O111 000
TW Hya
HD100546
HD163296
Fig. 28. O e iew o de ec ed emission o H2O110–101 (le ) and
111–000 ( igh ) wi h He schel-HIFI o TW Hya, HD 100456, HD 163296
and he s acked esul s o AA Tau, MWC 480, LkCa 15, and DM Tau.
Da a om Hoge heijde e al. (2011); Du e al. (2017), He schel a chi e
and Hoge heijde e al. (p i . comm.).
in eg a ion imes ( ypically >10 h) and hus lowes noise le els.
Fo all o he sou ces, obse ed o a ious ms le els, only uppe
limi s we e ob ained. Figu e 29 shows he de ec ions and uppe
Fig. 29. Line luminosi ies o models and obse a ions o o ho-H2O
110–101 o plane - o ming disks obse ed wi h He schel-HIFI. Solid
blue and ed lines show p edic ed line luminosi ies o a He big disk
model (blue) and a T Tau i disk model ( ed); see ex o de ails.
No e he loga i hmic scale. The e ec s o non-uni y illing ac o s a e
illus a ed by shaded lines a 50 and 25%. The obse a ional da a a e
om Hoge heijde e al. (2011); Du e al. (2017) and Hoge heijde e al.
(p i . comm.). Filled ci cles show de ec ions, blue o he He big s a
HD 100546 and ed o he T Tau i s a TW Hya. The g ay ci cles
connec ed by he solid g ay line show he de ec ed line luminosi y o
he s acked de ec ion o AA Tau, LkCa15, MWC 480 and DM Tau.
Down-poin ing iangles show uppe limi s (blue: He big disks; ed:
T Tau i disks). Da a a e plo ed e sus he obse ed size o he disk as
measu ed h ough CO emission (uppe panel) and mm-wa eleng h con-
inuum emission (lowe panel); o he s acked de ec ion (g ay line) he
ange o disk sizes is plo ed. Obse ed disk sizes a e aken om Walsh
e al. (2014); And ews e al. (2012); Loomis e al. (2017); Be gin e al.
(2016); Kudo e al. (2018); Jin e al. (2019); Qi e al. (2003); Liu e al.
(2019); Fedele e al. (2017); Huang e al. (2016); Du ey e al. (2003,
2016); Hughes e al. (2009); Macías e al. (2018); Isella e al. (2016);
Boehle e al. (2018); Huélamo e al. (2015); Clee es e al. (2016).
Line luminosi ies and disk sizes a e scaled o he la es Gaia dis ance
es ima es.
limi s in e ms o eloci y-in eg a ed line luminosi ies, using he
mos up- o-da e dis ances o he sou ces ob ained om Gaia.
Figu e 29 plo s he obse ed line luminosi ies and he uppe
limi s as unc ion o he gas and dus ou e adii o he disk
as measu ed in 12CO emission and h ough he mm-con inuum
emission. I also compa es he obse a ions o he expec ed
emission o a “ ypical” T Tau i disk ( ed) and a “ ypical”
He big Ae disk (blue). Fo he T Tau i disk, he TW Hya model
o Hoge heijde e al. (2011) and Salinas e al. (2016) is used: a
disk mass o 0.04 M, disk ou e adius o 200 au, and a disk
inclina ion o 7. Fo he He big disk, a model o he HD 100546
disk is adop ed (Hoge heijde e al., p i . comm.): a disk mass
o 0.01 M, a disk ou e adius o 400au, and a disk inclina-
ion o 42. In bo h cases, he disk empe a u e is calcula ed
A24, page 30 o 57
A&A 648, A24 (2021)
0
50
100
150
200
z(au)
a) log n(H2)(cm3)
4
5
6
7
8
9
0
50
100
150
200
z(au)
b) T(K)
20
40
60
80
100
120
140
160
180
200
0 100 200 300
R(au)
0
50
100
150
200
z(au)
c) log X(H2O)
132
50
100
12
11
10
9
8
7
6
5
4
Fig. 27. C oss sec ion o one quad an o a model o a He big disk,
ailo ed o ha a ound HD 100546. (a)H
2numbe densi y, (b) gas
empe a u e ( aken equal o he dus empe a u e), and (c) calcula ed
H2O abundance. Fu he de ails o he model can be ound in he ex
and e e ences. The H2O abundance can be di ided in h ee egions as
indica ed (see also Fig. 25).
20 0 20
-sou ce (km s1)
0
25
50
75
100
125
150
TMB (mK)
H2O110-101
TW Hya
HD100546
HD163296
AA Tau + MWC480
+ LkCa15 + DM Tau
x5
20 0 20
-sou ce (km s1)
H2O111 000
TW Hya
HD100546
HD163296
Fig. 28. O e iew o de ec ed emission o H2O110–101 (le ) and
111–000 ( igh ) wi h He schel-HIFI o TW Hya, HD 100456, HD 163296
and he s acked esul s o AA Tau, MWC 480, LkCa 15, and DM Tau.
Da a om Hoge heijde e al. (2011); Du e al. (2017), He schel a chi e
and Hoge heijde e al. (p i . comm.).
in eg a ion imes ( ypically >10 h) and hus lowes noise le els.
Fo all o he sou ces, obse ed o a ious ms le els, only uppe
limi s we e ob ained. Figu e 29 shows he de ec ions and uppe
Fig. 29. Line luminosi ies o models and obse a ions o o ho-H2O
110–101 o plane - o ming disks obse ed wi h He schel-HIFI. Solid
blue and ed lines show p edic ed line luminosi ies o a He big disk
model (blue) and a T Tau i disk model ( ed); see ex o de ails.
No e he loga i hmic scale. The e ec s o non-uni y illing ac o s a e
illus a ed by shaded lines a 50 and 25%. The obse a ional da a a e
om Hoge heijde e al. (2011); Du e al. (2017) and Hoge heijde e al.
(p i . comm.). Filled ci cles show de ec ions, blue o he He big s a
HD 100546 and ed o he T Tau i s a TW Hya. The g ay ci cles
connec ed by he solid g ay line show he de ec ed line luminosi y o
he s acked de ec ion o AA Tau, LkCa15, MWC 480 and DM Tau.
Down-poin ing iangles show uppe limi s (blue: He big disks; ed:
T Tau i disks). Da a a e plo ed e sus he obse ed size o he disk as
measu ed h ough CO emission (uppe panel) and mm-wa eleng h con-
inuum emission (lowe panel); o he s acked de ec ion (g ay line) he
ange o disk sizes is plo ed. Obse ed disk sizes a e aken om Walsh
e al. (2014); And ews e al. (2012); Loomis e al. (2017); Be gin e al.
(2016); Kudo e al. (2018); Jin e al. (2019); Qi e al. (2003); Liu e al.
(2019); Fedele e al. (2017); Huang e al. (2016); Du ey e al. (2003,
2016); Hughes e al. (2009); Macías e al. (2018); Isella e al. (2016);
Boehle e al. (2018); Huélamo e al. (2015); Clee es e al. (2016).
Line luminosi ies and disk sizes a e scaled o he la es Gaia dis ance
es ima es.
limi s in e ms o eloci y-in eg a ed line luminosi ies, using he
mos up- o-da e dis ances o he sou ces ob ained om Gaia.
Figu e 29 plo s he obse ed line luminosi ies and he uppe
limi s as unc ion o he gas and dus ou e adii o he disk
as measu ed in 12CO emission and h ough he mm-con inuum
emission. I also compa es he obse a ions o he expec ed
emission o a “ ypical” T Tau i disk ( ed) and a “ ypical”
He big Ae disk (blue). Fo he T Tau i disk, he TW Hya model
o Hoge heijde e al. (2011) and Salinas e al. (2016) is used: a
disk mass o 0.04 M, disk ou e adius o 200 au, and a disk
inclina ion o 7. Fo he He big disk, a model o he HD 100546
disk is adop ed (Hoge heijde e al., p i . comm.): a disk mass
o 0.01 M, a disk ou e adius o 400au, and a disk inclina-
ion o 42. In bo h cases, he disk empe a u e is calcula ed
A24, page 30 o 57
A&A 648, A24 (2021)
0
50
100
150
200
z(au)
a) log n(H2)(cm3)
4
5
6
7
8
9
0
50
100
150
200
z(au)
b) T(K)
20
40
60
80
100
120
140
160
180
200
0 100 200 300
R(au)
0
50
100
150
200
z(au)
c) log X(H2O)
132
50
100
12
11
10
9
8
7
6
5
4
Fig. 27. C oss sec ion o one quad an o a model o a He big disk,
ailo ed o ha a ound HD 100546. (a)H
2numbe densi y, (b) gas
empe a u e ( aken equal o he dus empe a u e), and (c) calcula ed
H2O abundance. Fu he de ails o he model can be ound in he ex
and e e ences. The H2O abundance can be di ided in h ee egions as
indica ed (see also Fig. 25).
20 0 20
-sou ce (km s1)
0
25
50
75
100
125
150
TMB (mK)
H2O110-101
TW Hya
HD100546
HD163296
AA Tau + MWC480
+ LkCa15 + DM Tau
x5
20 0 20
-sou ce (km s1)
H2O111 000
TW Hya
HD100546
HD163296
Fig. 28. O e iew o de ec ed emission o H2O110–101 (le ) and
111–000 ( igh ) wi h He schel-HIFI o TW Hya, HD 100456, HD 163296
and he s acked esul s o AA Tau, MWC 480, LkCa 15, and DM Tau.
Da a om Hoge heijde e al. (2011); Du e al. (2017), He schel a chi e
and Hoge heijde e al. (p i . comm.).
in eg a ion imes ( ypically >10 h) and hus lowes noise le els.
Fo all o he sou ces, obse ed o a ious ms le els, only uppe
limi s we e ob ained. Figu e 29 shows he de ec ions and uppe
Fig. 29. Line luminosi ies o models and obse a ions o o ho-H2O
110–101 o plane - o ming disks obse ed wi h He schel-HIFI. Solid
blue and ed lines show p edic ed line luminosi ies o a He big disk
model (blue) and a T Tau i disk model ( ed); see ex o de ails.
No e he loga i hmic scale. The e ec s o non-uni y illing ac o s a e
illus a ed by shaded lines a 50 and 25%. The obse a ional da a a e
om Hoge heijde e al. (2011); Du e al. (2017) and Hoge heijde e al.
(p i . comm.). Filled ci cles show de ec ions, blue o he He big s a
HD 100546 and ed o he T Tau i s a TW Hya. The g ay ci cles
connec ed by he solid g ay line show he de ec ed line luminosi y o
he s acked de ec ion o AA Tau, LkCa15, MWC 480 and DM Tau.
Down-poin ing iangles show uppe limi s (blue: He big disks; ed:
T Tau i disks). Da a a e plo ed e sus he obse ed size o he disk as
measu ed h ough CO emission (uppe panel) and mm-wa eleng h con-
inuum emission (lowe panel); o he s acked de ec ion (g ay line) he
ange o disk sizes is plo ed. Obse ed disk sizes a e aken om Walsh
e al. (2014); And ews e al. (2012); Loomis e al. (2017); Be gin e al.
(2016); Kudo e al. (2018); Jin e al. (2019); Qi e al. (2003); Liu e al.
(2019); Fedele e al. (2017); Huang e al. (2016); Du ey e al. (2003,
2016); Hughes e al. (2009); Macías e al. (2018); Isella e al. (2016);
Boehle e al. (2018); Huélamo e al. (2015); Clee es e al. (2016).
Line luminosi ies and disk sizes a e scaled o he la es Gaia dis ance
es ima es.
limi s in e ms o eloci y-in eg a ed line luminosi ies, using he
mos up- o-da e dis ances o he sou ces ob ained om Gaia.
Figu e 29 plo s he obse ed line luminosi ies and he uppe
limi s as unc ion o he gas and dus ou e adii o he disk
as measu ed in 12CO emission and h ough he mm-con inuum
emission. I also compa es he obse a ions o he expec ed
emission o a “ ypical” T Tau i disk ( ed) and a “ ypical”
He big Ae disk (blue). Fo he T Tau i disk, he TW Hya model
o Hoge heijde e al. (2011) and Salinas e al. (2016) is used: a
disk mass o 0.04 M, disk ou e adius o 200 au, and a disk
inclina ion o 7. Fo he He big disk, a model o he HD 100546
disk is adop ed (Hoge heijde e al., p i . comm.): a disk mass
o 0.01 M, a disk ou e adius o 400au, and a disk inclina-
ion o 42. In bo h cases, he disk empe a u e is calcula ed
A24, page 30 o 57
A&A 648, A24 (2021)
0
50
100
150
200
z(au)
a) log n(H2)(cm3)
4
5
6
7
8
9
0
50
100
150
200
z(au)
b) T(K)
20
40
60
80
100
120
140
160
180
200
0 100 200 300
R(au)
0
50
100
150
200
z(au)
c) log X(H2O)
132
50
100
12
11
10
9
8
7
6
5
4
Fig. 27. C oss sec ion o one quad an o a model o a He big disk,
ailo ed o ha a ound HD 100546. (a)H
2numbe densi y, (b) gas
empe a u e ( aken equal o he dus empe a u e), and (c) calcula ed
H2O abundance. Fu he de ails o he model can be ound in he ex
and e e ences. The H2O abundance can be di ided in h ee egions as
indica ed (see also Fig. 25).
20 0 20
-sou ce (km s1)
0
25
50
75
100
125
150
TMB (mK)
H2O110-101
TW Hya
HD100546
HD163296
AA Tau + MWC480
+ LkCa15 + DM Tau
x5
20 0 20
-sou ce (km s1)
H2O111 000
TW Hya
HD100546
HD163296
Fig. 28. O e iew o de ec ed emission o H2O110–101 (le ) and
111–000 ( igh ) wi h He schel-HIFI o TW Hya, HD 100456, HD 163296
and he s acked esul s o AA Tau, MWC 480, LkCa 15, and DM Tau.
Da a om Hoge heijde e al. (2011); Du e al. (2017), He schel a chi e
and Hoge heijde e al. (p i . comm.).
in eg a ion imes ( ypically >10 h) and hus lowes noise le els.
Fo all o he sou ces, obse ed o a ious ms le els, only uppe
limi s we e ob ained. Figu e 29 shows he de ec ions and uppe
Fig. 29. Line luminosi ies o models and obse a ions o o ho-H2O
110–101 o plane - o ming disks obse ed wi h He schel-HIFI. Solid
blue and ed lines show p edic ed line luminosi ies o a He big disk
model (blue) and a T Tau i disk model ( ed); see ex o de ails.
No e he loga i hmic scale. The e ec s o non-uni y illing ac o s a e
illus a ed by shaded lines a 50 and 25%. The obse a ional da a a e
om Hoge heijde e al. (2011); Du e al. (2017) and Hoge heijde e al.
(p i . comm.). Filled ci cles show de ec ions, blue o he He big s a
HD 100546 and ed o he T Tau i s a TW Hya. The g ay ci cles
connec ed by he solid g ay line show he de ec ed line luminosi y o
he s acked de ec ion o AA Tau, LkCa15, MWC 480 and DM Tau.
Down-poin ing iangles show uppe limi s (blue: He big disks; ed:
T Tau i disks). Da a a e plo ed e sus he obse ed size o he disk as
measu ed h ough CO emission (uppe panel) and mm-wa eleng h con-
inuum emission (lowe panel); o he s acked de ec ion (g ay line) he
ange o disk sizes is plo ed. Obse ed disk sizes a e aken om Walsh
e al. (2014); And ews e al. (2012); Loomis e al. (2017); Be gin e al.
(2016); Kudo e al. (2018); Jin e al. (2019); Qi e al. (2003); Liu e al.
(2019); Fedele e al. (2017); Huang e al. (2016); Du ey e al. (2003,
2016); Hughes e al. (2009); Macías e al. (2018); Isella e al. (2016);
Boehle e al. (2018); Huélamo e al. (2015); Clee es e al. (2016).
Line luminosi ies and disk sizes a e scaled o he la es Gaia dis ance
es ima es.
limi s in e ms o eloci y-in eg a ed line luminosi ies, using he
mos up- o-da e dis ances o he sou ces ob ained om Gaia.
Figu e 29 plo s he obse ed line luminosi ies and he uppe
limi s as unc ion o he gas and dus ou e adii o he disk
as measu ed in 12CO emission and h ough he mm-con inuum
emission. I also compa es he obse a ions o he expec ed
emission o a “ ypical” T Tau i disk ( ed) and a “ ypical”
He big Ae disk (blue). Fo he T Tau i disk, he TW Hya model
o Hoge heijde e al. (2011) and Salinas e al. (2016) is used: a
disk mass o 0.04 M, disk ou e adius o 200 au, and a disk
inclina ion o 7. Fo he He big disk, a model o he HD 100546
disk is adop ed (Hoge heijde e al., p i . comm.): a disk mass
o 0.01 M, a disk ou e adius o 400au, and a disk inclina-
ion o 42. In bo h cases, he disk empe a u e is calcula ed
A24, page 30 o 57
A&A 648, A24 (2021)
0
50
100
150
200
z(au)
a) log n(H2)(cm3)
4
5
6
7
8
9
0
50
100
150
200
z(au)
b) T(K)
20
40
60
80
100
120
140
160
180
200
0 100 200 300
R(au)
0
50
100
150
200
z(au)
c) log X(H2O)
132
50
100
12
11
10
9
8
7
6
5
4
Fig. 27. C oss sec ion o one quad an o a model o a He big disk,
ailo ed o ha a ound HD 100546. (a)H
2numbe densi y, (b) gas
empe a u e ( aken equal o he dus empe a u e), and (c) calcula ed
H2O abundance. Fu he de ails o he model can be ound in he ex
and e e ences. The H2O abundance can be di ided in h ee egions as
indica ed (see also Fig. 25).
20 0 20
-sou ce (km s1)
0
25
50
75
100
125
150
TMB (mK)
H2O110-101
TW Hya
HD100546
HD163296
AA Tau + MWC480
+ LkCa15 + DM Tau
x5
20 0 20
-sou ce (km s1)
H2O111 000
TW Hya
HD100546
HD163296
Fig. 28. O e iew o de ec ed emission o H2O110–101 (le ) and
111–000 ( igh ) wi h He schel-HIFI o TW Hya, HD 100456, HD 163296
and he s acked esul s o AA Tau, MWC 480, LkCa 15, and DM Tau.
Da a om Hoge heijde e al. (2011); Du e al. (2017), He schel a chi e
and Hoge heijde e al. (p i . comm.).
in eg a ion imes ( ypically >10 h) and hus lowes noise le els.
Fo all o he sou ces, obse ed o a ious ms le els, only uppe
limi s we e ob ained. Figu e 29 shows he de ec ions and uppe
Fig. 29. Line luminosi ies o models and obse a ions o o ho-H2O
110–101 o plane - o ming disks obse ed wi h He schel-HIFI. Solid
blue and ed lines show p edic ed line luminosi ies o a He big disk
model (blue) and a T Tau i disk model ( ed); see ex o de ails.
No e he loga i hmic scale. The e ec s o non-uni y illing ac o s a e
illus a ed by shaded lines a 50 and 25%. The obse a ional da a a e
om Hoge heijde e al. (2011); Du e al. (2017) and Hoge heijde e al.
(p i . comm.). Filled ci cles show de ec ions, blue o he He big s a
HD 100546 and ed o he T Tau i s a TW Hya. The g ay ci cles
connec ed by he solid g ay line show he de ec ed line luminosi y o
he s acked de ec ion o AA Tau, LkCa15, MWC 480 and DM Tau.
Down-poin ing iangles show uppe limi s (blue: He big disks; ed:
T Tau i disks). Da a a e plo ed e sus he obse ed size o he disk as
measu ed h ough CO emission (uppe panel) and mm-wa eleng h con-
inuum emission (lowe panel); o he s acked de ec ion (g ay line) he
ange o disk sizes is plo ed. Obse ed disk sizes a e aken om Walsh
e al. (2014); And ews e al. (2012); Loomis e al. (2017); Be gin e al.
(2016); Kudo e al. (2018); Jin e al. (2019); Qi e al. (2003); Liu e al.
(2019); Fedele e al. (2017); Huang e al. (2016); Du ey e al. (2003,
2016); Hughes e al. (2009); Macías e al. (2018); Isella e al. (2016);
Boehle e al. (2018); Huélamo e al. (2015); Clee es e al. (2016).
Line luminosi ies and disk sizes a e scaled o he la es Gaia dis ance
es ima es.
limi s in e ms o eloci y-in eg a ed line luminosi ies, using he
mos up- o-da e dis ances o he sou ces ob ained om Gaia.
Figu e 29 plo s he obse ed line luminosi ies and he uppe
limi s as unc ion o he gas and dus ou e adii o he disk
as measu ed in 12CO emission and h ough he mm-con inuum
emission. I also compa es he obse a ions o he expec ed
emission o a “ ypical” T Tau i disk ( ed) and a “ ypical”
He big Ae disk (blue). Fo he T Tau i disk, he TW Hya model
o Hoge heijde e al. (2011) and Salinas e al. (2016) is used: a
disk mass o 0.04 M, disk ou e adius o 200 au, and a disk
inclina ion o 7. Fo he He big disk, a model o he HD 100546
disk is adop ed (Hoge heijde e al., p i . comm.): a disk mass
o 0.01 M, a disk ou e adius o 400au, and a disk inclina-
ion o 42. In bo h cases, he disk empe a u e is calcula ed
A24, page 30 o 57
TW Hya HD 100546 AA Tau + MWC 480
+ LkCa 15 + DM Tau
(x5)
• Wa m wa e : mo e equen ly de ec ed
• Su ace laye s a e we
• Canno see he midplane whe e plane s o m
Obse a ions o wa e in disks
gas
H
α
e.g., Ca e al. 2004, 2008, 2011, Sally e al. 2008, 2011, 2015, Hoge heijde e al. 2011, Salinas e al. 2016,
Du e al. 2017, an Dishoeck e al. 2021, Pi o ano e al. 2022, Pe o i e al. 2023, Banza i e al. 2023, 2024
He schel and JWST

ALMA: HL Tau
• 3 H2O lines obus ly de ec ed wi h ALMA
• Ho 321 GHz line also seen in AS 205 acing snowline
Ca e al. 2018, Bosman e al. 2021, Facchini e al. 2024
Na u e As onomy
A icleh ps://doi.o g/10.1038/s41550-024-02207-w
Table 2 | Obse a ion IDs and execu ion block p ope ies, including sou ce in eg a ion ime, median PWV column,
bandpass, lux and phase calib a o s and maximum baseline
P og am ID Lines In eg a ion ime (min) PWV (mm) Bandpass/ lux calib a o s Phase calib a o s Maximum baseline (m)
2017.1.01178.S p-H2O 313–220 46 0.2 J0423-0120 J0510+1800 1,398
2017.1.01178.S p-H2O 515–422 31 0.4 J0538-4405 J0431+1731 3,637
2017.1.01178.S o-H2O 1029–936 33 0.5 J0519-4546 J0440+1437 8,547
2022.1.00905.S p-H2O 515–422 100 0.3 J0423-0120 J0431+1731 500
p-
H18
2O
515–422
1.7 mm con inuum H2O 183 GHz momen 0 H2O 183 GHz momen 1
km s–1
K km s–1
Ka
b
c
km s–1
K km s–1
K
2010
1.0
0.5
0
–0.5
–1.0
1.0
0.5
0
–0.5
–1.0
1.0 0.5
∆RA (a csec)
∆Dec (a csec)
∆RA (a csec) ∆RA (a csec)
–0.5 –1.0 1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
4 6 8 10
1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
0
1.0 0.5
∆RA (a csec)
–0.5 –1.00
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.00.2 0 –0.1 –0.21.0 0.5
∆RA (a csec)
–0.5 –1.00
0
20 30100
80 120 160400
K
80 120 160400
108647550250
H2O 325 GHz momen 1H2O 325 GHz momen 0
H2O 321 GHz momen 0
0.94 mm con inuum
0.94 mm con inuum 0.94 mm con inuum
∆Dec (a csec)
K
12040 800
1.0
0.5
0
–0.5
–1.0
∆Dec (a csec)
K km s–1
2001000
Fig. 1 | Con inuum in ensi y and wa e apou momen maps. a, Le , 1.7 mm
con inuum image o HL Tau. Cen e, in eg a ed in ensi y map o he 183 GHz wa e
line. Righ , in ensi y-weigh ed eloci y map o he 183 GHz wa e line a e 4σ
clipping on indi idual channels, whe e disk o a ion is clea ly de ec ed. b, Same as
a, o he 0.94 mm con inuum and he 325 GHz wa e line. The in ensi y-weigh ed
eloci y map in his case is compu ed a e 3σ clipping. c, le and cen e, same
as a, o he 0.94 mm con inuum and he 321 GHz wa e line. No momen 1 map is
shown due o low SNR. Righ , zoom-in o con inuum in ensi y, wi h [4,5,6,7,8]σ
con ou s o he 321 GHz line momen 0 map, wi h σ = 13.3 mJy beam−1 km s−1. The
.m.s. associa ed wi h he he in eg a ed in ensi y maps o he 183 and 325 GHz
lines a e, espec i ely, 28.2 and 46.3 mJy beam−1 km s−1. B igh ness in ensi y (K).
In eg a ed in ensi y (K km s−1). In ensi y weigh ed eloci y along he line o sigh
(km s−1). Dis ance om he phase cen e in Righ Ascension (Del a RA). Dis ance
om he same cen e in Declina ion (Del a Dec).
Na u e As onomy
A icleh ps://doi.o g/10.1038/s41550-024-02207-w
Table 2 | Obse a ion IDs and execu ion block p ope ies, including sou ce in eg a ion ime, median PWV column,
bandpass, lux and phase calib a o s and maximum baseline
P og am ID Lines In eg a ion ime (min) PWV (mm) Bandpass/ lux calib a o s Phase calib a o s Maximum baseline (m)
2017.1.01178.S p-H2O 313–220 46 0.2 J0423-0120 J0510+1800 1,398
2017.1.01178.S p-H2O 515–422 31 0.4 J0538-4405 J0431+1731 3,637
2017.1.01178.S o-H2O 1029–936 33 0.5 J0519-4546 J0440+1437 8,547
2022.1.00905.S p-H2O 515–422 100 0.3 J0423-0120 J0431+1731 500
p-
H18
2O
515–422
1.7 mm con inuum H2O 183 GHz momen 0 H2O 183 GHz momen 1
km s–1
K km s–1
Ka
b
c
km s–1
K km s–1
K
2010
1.0
0.5
0
–0.5
–1.0
1.0
0.5
0
–0.5
–1.0
1.0 0.5
∆RA (a csec)
∆Dec (a csec)
∆RA (a csec) ∆RA (a csec)
–0.5 –1.0 1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
4 6 8 10
1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
0
1.0 0.5
∆RA (a csec)
–0.5 –1.00
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.00.2 0 –0.1 –0.21.0 0.5
∆RA (a csec)
–0.5 –1.00
0
20 30100
80 120 160400
K
80 120 160400
108647550250
H2O 325 GHz momen 1H2O 325 GHz momen 0
H2O 321 GHz momen 0
0.94 mm con inuum
0.94 mm con inuum 0.94 mm con inuum
∆Dec (a csec)
K
12040 800
1.0
0.5
0
–0.5
–1.0
∆Dec (a csec)
K km s–1
2001000
Fig. 1 | Con inuum in ensi y and wa e apou momen maps. a, Le , 1.7 mm
con inuum image o HL Tau. Cen e, in eg a ed in ensi y map o he 183 GHz wa e
line. Righ , in ensi y-weigh ed eloci y map o he 183 GHz wa e line a e 4σ
clipping on indi idual channels, whe e disk o a ion is clea ly de ec ed. b, Same as
a, o he 0.94 mm con inuum and he 325 GHz wa e line. The in ensi y-weigh ed
eloci y map in his case is compu ed a e 3σ clipping. c, le and cen e, same
as a, o he 0.94 mm con inuum and he 321 GHz wa e line. No momen 1 map is
shown due o low SNR. Righ , zoom-in o con inuum in ensi y, wi h [4,5,6,7,8]σ
con ou s o he 321 GHz line momen 0 map, wi h σ = 13.3 mJy beam−1 km s−1. The
.m.s. associa ed wi h he he in eg a ed in ensi y maps o he 183 and 325 GHz
lines a e, espec i ely, 28.2 and 46.3 mJy beam−1 km s−1. B igh ness in ensi y (K).
In eg a ed in ensi y (K km s−1). In ensi y weigh ed eloci y along he line o sigh
(km s−1). Dis ance om he phase cen e in Righ Ascension (Del a RA). Dis ance
om he same cen e in Declina ion (Del a Dec).
Na u e As onomy
A icleh ps://doi.o g/10.1038/s41550-024-02207-w
Table 2 | Obse a ion IDs and execu ion block p ope ies, including sou ce in eg a ion ime, median PWV column,
bandpass, lux and phase calib a o s and maximum baseline
P og am ID Lines In eg a ion ime (min) PWV (mm) Bandpass/ lux calib a o s Phase calib a o s Maximum baseline (m)
2017.1.01178.S p-H2O 313–220 46 0.2 J0423-0120 J0510+1800 1,398
2017.1.01178.S p-H2O 515–422 31 0.4 J0538-4405 J0431+1731 3,637
2017.1.01178.S o-H2O 1029–936 33 0.5 J0519-4546 J0440+1437 8,547
2022.1.00905.S p-H2O 515–422 100 0.3 J0423-0120 J0431+1731 500
p-
H18
2O
515–422
1.7 mm con inuum H2O 183 GHz momen 0 H2O 183 GHz momen 1
km s–1
K km s–1
Ka
b
c
km s–1
K km s–1
K
2010
1.0
0.5
0
–0.5
–1.0
1.0
0.5
0
–0.5
–1.0
1.0 0.5
∆RA (a csec)
∆Dec (a csec)
∆RA (a csec) ∆RA (a csec)
–0.5 –1.0 1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
4 6 8 10
1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
0
1.0 0.5
∆RA (a csec)
–0.5 –1.00
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.00.2 0 –0.1 –0.21.0 0.5
∆RA (a csec)
–0.5 –1.00
0
20 30100
80 120 160400
K
80 120 160400
108647550250
H2O 325 GHz momen 1H2O 325 GHz momen 0
H2O 321 GHz momen 0
0.94 mm con inuum
0.94 mm con inuum 0.94 mm con inuum
∆Dec (a csec)
K
12040 800
1.0
0.5
0
–0.5
–1.0
∆Dec (a csec)
K km s–1
2001000
Fig. 1 | Con inuum in ensi y and wa e apou momen maps. a, Le , 1.7 mm
con inuum image o HL Tau. Cen e, in eg a ed in ensi y map o he 183 GHz wa e
line. Righ , in ensi y-weigh ed eloci y map o he 183 GHz wa e line a e 4σ
clipping on indi idual channels, whe e disk o a ion is clea ly de ec ed. b, Same as
a, o he 0.94 mm con inuum and he 325 GHz wa e line. The in ensi y-weigh ed
eloci y map in his case is compu ed a e 3σ clipping. c, le and cen e, same
as a, o he 0.94 mm con inuum and he 321 GHz wa e line. No momen 1 map is
shown due o low SNR. Righ , zoom-in o con inuum in ensi y, wi h [4,5,6,7,8]σ
con ou s o he 321 GHz line momen 0 map, wi h σ = 13.3 mJy beam−1 km s−1. The
.m.s. associa ed wi h he he in eg a ed in ensi y maps o he 183 and 325 GHz
lines a e, espec i ely, 28.2 and 46.3 mJy beam−1 km s−1. B igh ness in ensi y (K).
In eg a ed in ensi y (K km s−1). In ensi y weigh ed eloci y along he line o sigh
(km s−1). Dis ance om he phase cen e in Righ Ascension (Del a RA). Dis ance
om he same cen e in Declina ion (Del a Dec).
Na u e As onomy
A icleh ps://doi.o g/10.1038/s41550-024-02207-w
Table 2 | Obse a ion IDs and execu ion block p ope ies, including sou ce in eg a ion ime, median PWV column,
bandpass, lux and phase calib a o s and maximum baseline
P og am ID Lines In eg a ion ime (min) PWV (mm) Bandpass/ lux calib a o s Phase calib a o s Maximum baseline (m)
2017.1.01178.S p-H2O 313–220 46 0.2 J0423-0120 J0510+1800 1,398
2017.1.01178.S p-H2O 515–422 31 0.4 J0538-4405 J0431+1731 3,637
2017.1.01178.S o-H2O 1029–936 33 0.5 J0519-4546 J0440+1437 8,547
2022.1.00905.S p-H2O 515–422 100 0.3 J0423-0120 J0431+1731 500
p-
H18
2O
515–422
1.7 mm con inuum H2O 183 GHz momen 0 H2O 183 GHz momen 1
km s–1
K km s–1
Ka
b
c
km s–1
K km s–1
K
2010
1.0
0.5
0
–0.5
–1.0
1.0
0.5
0
–0.5
–1.0
1.0 0.5
∆RA (a csec)
∆Dec (a csec)
∆RA (a csec) ∆RA (a csec)
–0.5 –1.0 1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
4 6 8 10
1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
0
1.0 0.5
∆RA (a csec)
–0.5 –1.00
∆RA (a csec)
1.0 0.5 0 –0.5 –1.0
∆RA (a csec)
1.00.2 0 –0.1 –0.21.0 0.5
∆RA (a csec)
–0.5 –1.00
0
20 30100
80 120 160400
K
80 120 160400
108647550250
H2O 325 GHz momen 1H2O 325 GHz momen 0
H2O 321 GHz momen 0
0.94 mm con inuum
0.94 mm con inuum 0.94 mm con inuum
∆Dec (a csec)
K
12040 800
1.0
0.5
0
–0.5
–1.0
∆Dec (a csec)
K km s–1
2001000
Fig. 1 | Con inuum in ensi y and wa e apou momen maps. a, Le , 1.7 mm
con inuum image o HL Tau. Cen e, in eg a ed in ensi y map o he 183 GHz wa e
line. Righ , in ensi y-weigh ed eloci y map o he 183 GHz wa e line a e 4σ
clipping on indi idual channels, whe e disk o a ion is clea ly de ec ed. b, Same as
a, o he 0.94 mm con inuum and he 325 GHz wa e line. The in ensi y-weigh ed
eloci y map in his case is compu ed a e 3σ clipping. c, le and cen e, same
as a, o he 0.94 mm con inuum and he 321 GHz wa e line. No momen 1 map is
shown due o low SNR. Righ , zoom-in o con inuum in ensi y, wi h [4,5,6,7,8]σ
con ou s o he 321 GHz line momen 0 map, wi h σ = 13.3 mJy beam−1 km s−1. The
.m.s. associa ed wi h he he in eg a ed in ensi y maps o he 183 and 325 GHz
lines a e, espec i ely, 28.2 and 46.3 mJy beam−1 km s−1. B igh ness in ensi y (K).
In eg a ed in ensi y (K km s−1). In ensi y weigh ed eloci y along he line o sigh
(km s−1). Dis ance om he phase cen e in Righ Ascension (Del a RA). Dis ance
om he same cen e in Declina ion (Del a Dec).
Eup = 205 K Eup = 470 K Eup = 1861 K
Obse a ions o wa e in disks
Obse a ions o wa e in disks
• Wa e is a ely seen in disks
• Whe e does wa e go?
Edi ed om: Bill Sax on AUI/NRAO
Inhe i ance
Edi ed om: Bill Sax on AUI/NRAO
Newly
o med
Rese
• Many molecules seen in he ea lies phases o s a and plane o ma ion
• Gas-phase molecules collide ~1/mon h
• G ains a e essen ial o o m
molecules
• H2O, CH3OH, NH3, NH4, …
G ains a e essen ial o chemical complexi y
O
H
H
McClu e e al. 2023

•ISM D/H = 2 x 10-5 (Linsky e al. 2003)
•H3+ + HD H2D+ + H2 +230 K
• Laye ed ice s uc u e wi h diffe en
deg ees o deu e a ion
Laye ing o wa e iso opologues
Deu e a ion
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
A24, page 7 o 57
H2O
H2O
HDO
D2O
cloud dense co e
• T > 25 K
• D no effec i e
• H2O
• T < 25 K
• D is effec i e
• HDO, D2O
Wa son e al. 1976, Aikawa e al. 1999, Sipilä, e al. 2015, an Dishoeck e al. 2021
Dis inguishing inhe i ance s ep ocessing
A&A 599, A40 (2017)
s ella UV adia ion. In ou model, FCRUV is cons an , 104pho-
ons cm2s1, o simplici y, neglec ing an a enua ion e↵ec o
cosmic ays o la ge column densi ies (Umebayashi & Nakano
1981). I is wo h men ioning again ha he disk is hea ily
shielded om he s ella UV i adia ion (Fig. 1). F =1, i.e.,
when he cosmic ay-induced UV domina es o e he s ella UV,
co esponds o ⇠2⇥107inciden UV pho ons pe one dus g ain
up o acc in ou model.
Figu e 7shows he abundances o H2O ice ( op) and HDO
ice (middle), and he HDO/H2O ice a io (bo om) as unc ions
o F in he luid pa cels which a e loca ed in he disk a = acc.
I is clea ha he cosmic ay-induced UV has a negligible impac
on he wa e ice abundances, while he s ella UV domina es he
wa e ice chemis y. An an i-co ela ion be ween he UV luence
and he H2O ice abundance is seen especially a F &500. The
dashed blue and ed lines in he igu e ep esen he expec ed wa-
e ice abundances as unc ions o F when only pho odeso p ion
is an allowed chemical p ocess and when only pho odissocia ion
and pho odeso p ion a e allowed, espec i ely,
xHXOice (F )=x0
HXOice (⌃jbj)⇥R o
ph,HXOice acc,(5)
whe e x0
HXOice is he abundance o HXO ice, whe e X is H o D,
in pa cels wi h F ⇠1. R o
ph,HXOice is simila o Eq. (2) bu ng and
FUV a e eplaced by he abundance o dus g ains and he ime-
a e aged lux along a s eamline, F ⇥FCRUV, espec i ely. On
he e alua ion o Eq. (5), ✓H2Owas se o be 0.35 (i.e., he es o
he ice man le consis s o o he species), which comes om he
a e age ac ion o H2O in he opmos ⇠50 MLs o he ice man-
le a he onse o collapse (c . Fig. 2). Tha is smalle han he
a e age ac ion o H2O in he en i e ice man le, ⇠0.5, bu la ge
han he su ace co e age o H2O ice, ⇠0.2. The pa ame e bjis
he b anching a io o each ou come jo H2O ice pho odissoci-
a ion (A asa e al. 2015). I is clea ha he pho odissocia ion o
H2O ice is much mo e impo an o H2O ice des uc ion han
pho odeso p ion. Gi en he wa m empe a u e o he p o os ella
en elope (&20–30 K, see Fig. 1), which educes he p obabili y
o hyd ogena ion on he g ain su ace upon H a om adso p ion,
he e o ma ion o H2O ice is no e icien enough o compensa e
o i s pho odissocia ion. Howe e , conside ing he nume ical
da a a e (well) abo e he ed line, he e o ma ion o H2O ice is
no negligible. The sca e in he H2O ice abundance a he high
luence egime likely comes om he di↵e ence in he dus em-
pe a u e when wa e ice is (pa ly) e o med. The e o ma ion o
H2O ice ia OHice +Hice compe es wi h he o ma ion o CO2ice
ia OHice +COice, he la e o which becomes mo e a o able
wi h inc easing dus empe a u e. A highe dus empe a u es
(&40–50 K), whe e su ace chemis y is ine icien , gaseous O2
is he dominan p oduc o wa e ice des uc ion, which o ms
ia he neu al-neu al eac ion in he gas phase, OH +O (see
also D ozdo skaya e al. 2016;Taque e al. 2016).
The HDO ice abundance and he HDO/H2O ice a io show
mo e complex beha io : hey s a o d op a F ⇠100, while
in he highe luence egime, whe e H2O ice s a s o be la gely
des oyed and pa ly e o med, he HDO ice abundance and he
HDO/H2O ice a io end o s ay cons an o inc ease wi h he
luence. The o me indica es again ha he HDO ice abun-
dance is mo e sensi i e o he pho ochemis y han ha o H2O
ice; he uppe ice laye s whe e mos HDO is p esen a e los
p io o he lowe ice laye s whe e mos H2O is p esen . The ed
line in he middle panel shows Eq. (5) o HDO wi h ✓HDO o
2⇥103(c . Fig. 2). The line ep oduces he nume ical da a a
F .200. The beha io o he HDO ice abundance in he highe
1 10 100 1000
10-5
10-4
H2O ice [nH]
1 10 100 1000
10-9
10-8
10-7
10-6
10-5
HDO ice [nH]
1 10 100 1000
No malized FUV luence
10-6
10-4
10-2
1
102
Abundance a io
(D2O/HDO)/(HDO/H2O)
HDO/H2O
D2O/H2O
Fig. 7. H2O ice ( op) and HDO ice (middle) abundances in he luid
pa cels ha a e loca ed in he disk a = acc as unc ions o he
no malized UV luence. The bo om panel shows HDO/H2O ice a io
(black), D2O/H2O ice a io (ligh g ay), and he a io o D2O/HDO o
HDO/H2O ice a io (g ay). Only he luid pa cels in which he H2O ice
abundance is la ge han 105a e plo ed. The blue and ed dashed lines
depic he expec ed H2O (o HDO) ice abundance when only pho odes-
o p ion is an allowed chemical p ocess and when only pho odissocia-
ion and pho odeso p ion a e included, espec i ely. See he main ex
o mo e de ails.
luence egime indica es ha he le el o deu e ium ac iona ion
in e o med wa e ice is simila o o highe han ha in he o igi-
nal wa e ice (i.e., wa e ice be o e he des uc ion). This implies
ha using he HDO/H2O a io as a p obe o he p es ella inhe -
i ance o H2O is limi ed because he HDO/H2O a io does no
enable a dis inc ion be ween he o iginal and e o med ice. Al-
e na i ely, in he bo om panel o Fig. 7, i is seen ha he a io
o D2O/HDO o HDO/H2O is di↵e en be ween he o iginal and
e o med wa e ice. This implies ha he a io o D2O/HDO o
HDO/H2O is a be e p obe o he p es ella inhe i ance o H2O
han solely he HDO/H2O a io. We discuss his p obe o he
p es ella inhe i ance in mo e de ail in Sec . 6.1.
The a ionale o he high HDO/H2O a io in he e o med
wa e ice is wo old: i s , he pho o agmen s a e highly en-
iched in deu e ium as he o iginal ice was highly en iched in
deu e ium, and, second, i akes some ime o he pho o ag-
men s o each he equilib ium le el (i.e., low le el) o deu e ium
ac iona ion a he wa m empe a u es o he en elope ia gas-
phase ion-neu al chemis y. Then, i he imescale o ice e -
o ma ion is sho e han he elaxa ion imescale o deu e ium
ac iona ion, he ac iona ion in he pho o agmen s (i.e., he
o iginal ice) is ans e ed o he e o med ice. This is he case in
ou model. Addi ionally he e a e pa hways o deu e ium ac-
iona ion in he gas phase ha can wo k e en a wa m gas em-
pe a u es, e.g., OH +D!OD +H+810 K (Milla e al. 1989;
A40, page 8 o 18
UV luence = e olu ion
UV
Fu uya e al. 2017
• G ains exposed o UV om cloud o
disk
• UV adia ion des oys HDO and D2O
in ou e laye
• HDO/H2O aces inhe i ance s
ese *
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
A24, page 7 o 57
H2O
HDO
D2O
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
A24, page 7 o 57
H2O
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
A24, page 7 o 57
H2O
Wa e ail: HDO/H2O
• T ail o wa e om clouds
o plane s is unclea :
• inhe i ance (Visse e al. 2009;
D ozdo skaya e al. 2016)
• ep ocessing (e.g. Yang e al.
2013)
• Disks a e missing!
Sp inge Na u e 2021 L
A
T
EX empla e
10 Wa e D/H a io in a P o o-plane a y Disk
Fig. 4 HDO/H2O a io o Class 0 p o os a s, V883 O i, Jupi e Family
come s (JFC, wi h 67P labeled), Oo Cloud come s (OCC), Ea h’s oceans,
he Sun, and he local in e s ella medium (ISM). The poin s a e a anged
o highligh a po en ial e olu iona y scena io wi h he o ming p o os a s on
he igh , he ‘e ol ed’ Sola Sys em bodies on he le , and V883 O i ills
in a egion o pa ame e space o a young p o o-plane a y disk, jus p io
o o con empo aneous wi h plane o ma ion. The ellipses d awn a ound he
di↵e en g oups a e mean o guide he eye, bu he ho izon al lines wi hin
each ellipse deno e he mean HDO/H2O a io o each g oup, and he e ical
lines associa ed wi h each poin ep esen he 1 s.d. unce ain ies. I a e ical
line is no isible, he unce ain y is less han he size o he symbol. In he
con ex o o he measu emen s, V883 O i indica es ha he HDO/H2O a io
does no s ongly e ol e om he p o os a phase o he disk, p o iding u he
obse a ional e idence ha he wa e is di ec ly inhe i ed om he en elope o
he disk wi hou signi ican chemical changes. Mo eo e , he HDO/H2O a io
o come s a e simila o V883 O i (bu sligh ly below), indica ing ha he
ma e ial we p obe in he gas phase wi hin he disk o V883 O i is simila o he
ma e ial ha becomes inco po a ed in o come s. The indi idual measu emen s
a e abula ed in he Me hods sec ion (Ex ended Da a Table 5.)
ime
Pe sson e al. 2014, Jensen e al. 2019, 2021, Al wegg e al.
2015, 2019, Clee es e e al. 2014, Fu uya e al. 2016, 2017
?
ongoing plane o ma ion
80 au
e.g., Cieza e al. 2016,
an ’ Hoff e al. 2018,
Leemke e al. 2021
V883 O i
wa e snowline
HDO and H218O emission
• HDO & H218O —> D/H
• HDO/H2O =
(2.26 ±0.63) ×10−3
Sp inge Na u e 2021 L
A
T
EX empla e
8Wa e D/H a io in a P o o-plane a y Disk
Fig. 2 In eg a ed in ensi y images o wa e and o he molecula lines in he
disk o V883 O i. We show he HDO 225 GHz line (a), he H218O 203 GHz
line (b), CH3OH (c), and C17O (d), as he colo scale, while he ou e ex en
o he dus con inuum emission is shown as a whi e con ou ; he in eg a ed
in ensi y maps we e ex ac ed om he da a using he Keple ian
masks. The whi e c oss ma ks he loca ion o he con inuum emission peak
and he posi ion o he p o os a . The HDO and H218O lines show a ing o
emission ha is smalle in adial ex en han he con inuum and C17O
emission. The CH3OH (me hanol) image shows a e y simila s uc u e and
ex en ela i e o he HDO and H218Olines.C
17O mo e ully aces he ex en
o he disk gas emission wi h i s lowe sublima ion empe a u e o ⇠25 K,
ex ending beyond he con inuum emission. The cen al dep ession in emission
o all lines is he esul o op ically hick con inuum emission a enua ing
he molecula emission a adii smalle han ⇠40 au (0.
001); he ex en o his
op ically hick egion is deno ed wi h he dashed hick g ay line in he cen e
o each image. The ellipses in he lowe igh co ne deno e he esolu ion o
he line obse a ions (o ange, ⇠0.100) and he con inuum (whi e, ⇠0.
0008).
Sp inge Na u e 2021 L
A
T
EX empla e
8Wa e D/H a io in a P o o-plane a y Disk
Fig. 2 In eg a ed in ensi y images o wa e and o he molecula lines in he
disk o V883 O i. We show he HDO 225 GHz line (a), he H218O 203 GHz
line (b), CH3OH (c), and C17O (d), as he colo scale, while he ou e ex en
o he dus con inuum emission is shown as a whi e con ou ; he in eg a ed
in ensi y maps we e ex ac ed om he da a using he Keple ian
masks. The whi e c oss ma ks he loca ion o he con inuum emission peak
and he posi ion o he p o os a . The HDO and H218O lines show a ing o
emission ha is smalle in adial ex en han he con inuum and C17O
emission. The CH3OH (me hanol) image shows a e y simila s uc u e and
ex en ela i e o he HDO and H218Olines.C
17O mo e ully aces he ex en
o he disk gas emission wi h i s lowe sublima ion empe a u e o ⇠25 K,
ex ending beyond he con inuum emission. The cen al dep ession in emission
o all lines is he esul o op ically hick con inuum emission a enua ing
he molecula emission a adii smalle han ⇠40 au (0.
001); he ex en o his
op ically hick egion is deno ed wi h he dashed hick g ay line in he cen e
o each image. The ellipses in he lowe igh co ne deno e he esolu ion o
he line obse a ions (o ange, ⇠0.100) and he con inuum (whi e, ⇠0.
0008).
Tobin, an ’ Hoff, Leemke , e al. 2023
HDO H218O

High deu e a ion in HDO/H2O in V883 O i
• HDO & H218O —> D/H
• HDO/H2O =
• Simila o Class 0 &
come s
• No signi ican chemical
al e a ion o wa e
(2.26 ±0.63) ×10−3
Tobin, an ’ Hoff, Leemke , e al. 2023
Sp inge Na u e 2021 L
A
T
EX empla e
10 Wa e D/H a io in a P o o-plane a y Disk
Fig. 4 HDO/H2O a io o Class 0 p o os a s, V883 O i, Jupi e Family
come s (JFC, wi h 67P labeled), Oo Cloud come s (OCC), Ea h’s oceans,
he Sun, and he local in e s ella medium (ISM). The poin s a e a anged
o highligh a po en ial e olu iona y scena io wi h he o ming p o os a s on
he igh , he ‘e ol ed’ Sola Sys em bodies on he le , and V883 O i ills
in a egion o pa ame e space o a young p o o-plane a y disk, jus p io
o o con empo aneous wi h plane o ma ion. The ellipses d awn a ound he
di↵e en g oups a e mean o guide he eye, bu he ho izon al lines wi hin
each ellipse deno e he mean HDO/H2O a io o each g oup, and he e ical
lines associa ed wi h each poin ep esen he 1 s.d. unce ain ies. I a e ical
line is no isible, he unce ain y is less han he size o he symbol. In he
con ex o o he measu emen s, V883 O i indica es ha he HDO/H2O a io
does no s ongly e ol e om he p o os a phase o he disk, p o iding u he
obse a ional e idence ha he wa e is di ec ly inhe i ed om he en elope o
he disk wi hou signi ican chemical changes. Mo eo e , he HDO/H2O a io
o come s a e simila o V883 O i (bu sligh ly below), indica ing ha he
ma e ial we p obe in he gas phase wi hin he disk o V883 O i is simila o he
ma e ial ha becomes inco po a ed in o come s. The indi idual measu emen s
a e abula ed in he Me hods sec ion (Ex ended Da a Table 5.)
ongoing plane o ma ion
ime
Pe sson e al. 2014, Jensen e al. 2019, 2021, Al wegg e al.
2015, 2019, Clee es e e al. 2014, Fu uya e al. 2016, 2017
Dis inguishing inhe i ance s ep ocessing
A&A 599, A40 (2017)
s ella UV adia ion. In ou model, FCRUV is cons an , 104pho-
ons cm2s1, o simplici y, neglec ing an a enua ion e↵ec o
cosmic ays o la ge column densi ies (Umebayashi & Nakano
1981). I is wo h men ioning again ha he disk is hea ily
shielded om he s ella UV i adia ion (Fig. 1). F =1, i.e.,
when he cosmic ay-induced UV domina es o e he s ella UV,
co esponds o ⇠2⇥107inciden UV pho ons pe one dus g ain
up o acc in ou model.
Figu e 7shows he abundances o H2O ice ( op) and HDO
ice (middle), and he HDO/H2O ice a io (bo om) as unc ions
o F in he luid pa cels which a e loca ed in he disk a = acc.
I is clea ha he cosmic ay-induced UV has a negligible impac
on he wa e ice abundances, while he s ella UV domina es he
wa e ice chemis y. An an i-co ela ion be ween he UV luence
and he H2O ice abundance is seen especially a F &500. The
dashed blue and ed lines in he igu e ep esen he expec ed wa-
e ice abundances as unc ions o F when only pho odeso p ion
is an allowed chemical p ocess and when only pho odissocia ion
and pho odeso p ion a e allowed, espec i ely,
xHXOice (F )=x0
HXOice (⌃jbj)⇥R o
ph,HXOice acc,(5)
whe e x0
HXOice is he abundance o HXO ice, whe e X is H o D,
in pa cels wi h F ⇠1. R o
ph,HXOice is simila o Eq. (2) bu ng and
FUV a e eplaced by he abundance o dus g ains and he ime-
a e aged lux along a s eamline, F ⇥FCRUV, espec i ely. On
he e alua ion o Eq. (5), ✓H2Owas se o be 0.35 (i.e., he es o
he ice man le consis s o o he species), which comes om he
a e age ac ion o H2O in he opmos ⇠50 MLs o he ice man-
le a he onse o collapse (c . Fig. 2). Tha is smalle han he
a e age ac ion o H2O in he en i e ice man le, ⇠0.5, bu la ge
han he su ace co e age o H2O ice, ⇠0.2. The pa ame e bjis
he b anching a io o each ou come jo H2O ice pho odissoci-
a ion (A asa e al. 2015). I is clea ha he pho odissocia ion o
H2O ice is much mo e impo an o H2O ice des uc ion han
pho odeso p ion. Gi en he wa m empe a u e o he p o os ella
en elope (&20–30 K, see Fig. 1), which educes he p obabili y
o hyd ogena ion on he g ain su ace upon H a om adso p ion,
he e o ma ion o H2O ice is no e icien enough o compensa e
o i s pho odissocia ion. Howe e , conside ing he nume ical
da a a e (well) abo e he ed line, he e o ma ion o H2O ice is
no negligible. The sca e in he H2O ice abundance a he high
luence egime likely comes om he di↵e ence in he dus em-
pe a u e when wa e ice is (pa ly) e o med. The e o ma ion o
H2O ice ia OHice +Hice compe es wi h he o ma ion o CO2ice
ia OHice +COice, he la e o which becomes mo e a o able
wi h inc easing dus empe a u e. A highe dus empe a u es
(&40–50 K), whe e su ace chemis y is ine icien , gaseous O2
is he dominan p oduc o wa e ice des uc ion, which o ms
ia he neu al-neu al eac ion in he gas phase, OH +O (see
also D ozdo skaya e al. 2016;Taque e al. 2016).
The HDO ice abundance and he HDO/H2O ice a io show
mo e complex beha io : hey s a o d op a F ⇠100, while
in he highe luence egime, whe e H2O ice s a s o be la gely
des oyed and pa ly e o med, he HDO ice abundance and he
HDO/H2O ice a io end o s ay cons an o inc ease wi h he
luence. The o me indica es again ha he HDO ice abun-
dance is mo e sensi i e o he pho ochemis y han ha o H2O
ice; he uppe ice laye s whe e mos HDO is p esen a e los
p io o he lowe ice laye s whe e mos H2O is p esen . The ed
line in he middle panel shows Eq. (5) o HDO wi h ✓HDO o
2⇥103(c . Fig. 2). The line ep oduces he nume ical da a a
F .200. The beha io o he HDO ice abundance in he highe
1 10 100 1000
10-5
10-4
H2O ice [nH]
1 10 100 1000
10-9
10-8
10-7
10-6
10-5
HDO ice [nH]
1 10 100 1000
No malized FUV luence
10-6
10-4
10-2
1
102
Abundance a io
(D2O/HDO)/(HDO/H2O)
HDO/H2O
D2O/H2O
Fig. 7. H2O ice ( op) and HDO ice (middle) abundances in he luid
pa cels ha a e loca ed in he disk a = acc as unc ions o he
no malized UV luence. The bo om panel shows HDO/H2O ice a io
(black), D2O/H2O ice a io (ligh g ay), and he a io o D2O/HDO o
HDO/H2O ice a io (g ay). Only he luid pa cels in which he H2O ice
abundance is la ge han 105a e plo ed. The blue and ed dashed lines
depic he expec ed H2O (o HDO) ice abundance when only pho odes-
o p ion is an allowed chemical p ocess and when only pho odissocia-
ion and pho odeso p ion a e included, espec i ely. See he main ex
o mo e de ails.
luence egime indica es ha he le el o deu e ium ac iona ion
in e o med wa e ice is simila o o highe han ha in he o igi-
nal wa e ice (i.e., wa e ice be o e he des uc ion). This implies
ha using he HDO/H2O a io as a p obe o he p es ella inhe -
i ance o H2O is limi ed because he HDO/H2O a io does no
enable a dis inc ion be ween he o iginal and e o med ice. Al-
e na i ely, in he bo om panel o Fig. 7, i is seen ha he a io
o D2O/HDO o HDO/H2O is di↵e en be ween he o iginal and
e o med wa e ice. This implies ha he a io o D2O/HDO o
HDO/H2O is a be e p obe o he p es ella inhe i ance o H2O
han solely he HDO/H2O a io. We discuss his p obe o he
p es ella inhe i ance in mo e de ail in Sec . 6.1.
The a ionale o he high HDO/H2O a io in he e o med
wa e ice is wo old: i s , he pho o agmen s a e highly en-
iched in deu e ium as he o iginal ice was highly en iched in
deu e ium, and, second, i akes some ime o he pho o ag-
men s o each he equilib ium le el (i.e., low le el) o deu e ium
ac iona ion a he wa m empe a u es o he en elope ia gas-
phase ion-neu al chemis y. Then, i he imescale o ice e -
o ma ion is sho e han he elaxa ion imescale o deu e ium
ac iona ion, he ac iona ion in he pho o agmen s (i.e., he
o iginal ice) is ans e ed o he e o med ice. This is he case in
ou model. Addi ionally he e a e pa hways o deu e ium ac-
iona ion in he gas phase ha can wo k e en a wa m gas em-
pe a u es, e.g., OH +D!OD +H+810 K (Milla e al. 1989;
A40, page 8 o 18
UV luence = e olu ion
UV
Fu uya e al. 2017
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
A24, page 7 o 57
H2O
• HDO/H2O aces inhe i ance s
ese *
• HDO/H2O can be high e en i
wa e is ep ocessed!
• O he ace s o inhe i ance s
ep ocessing a e needed
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
A24, page 7 o 57
H2O
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
A24, page 7 o 57
H2O
HDO
D2O
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
A24, page 7 o 57
H2O
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
A24, page 7 o 57
H2O
HDO
D2O
Dis inguishing inhe i ance s ep ocessing
A&A 599, A40 (2017)
s ella UV adia ion. In ou model, FCRUV is cons an , 104pho-
ons cm2s1, o simplici y, neglec ing an a enua ion e↵ec o
cosmic ays o la ge column densi ies (Umebayashi & Nakano
1981). I is wo h men ioning again ha he disk is hea ily
shielded om he s ella UV i adia ion (Fig. 1). F =1, i.e.,
when he cosmic ay-induced UV domina es o e he s ella UV,
co esponds o ⇠2⇥107inciden UV pho ons pe one dus g ain
up o acc in ou model.
Figu e 7shows he abundances o H2O ice ( op) and HDO
ice (middle), and he HDO/H2O ice a io (bo om) as unc ions
o F in he luid pa cels which a e loca ed in he disk a = acc.
I is clea ha he cosmic ay-induced UV has a negligible impac
on he wa e ice abundances, while he s ella UV domina es he
wa e ice chemis y. An an i-co ela ion be ween he UV luence
and he H2O ice abundance is seen especially a F &500. The
dashed blue and ed lines in he igu e ep esen he expec ed wa-
e ice abundances as unc ions o F when only pho odeso p ion
is an allowed chemical p ocess and when only pho odissocia ion
and pho odeso p ion a e allowed, espec i ely,
xHXOice (F )=x0
HXOice (⌃jbj)⇥R o
ph,HXOice acc,(5)
whe e x0
HXOice is he abundance o HXO ice, whe e X is H o D,
in pa cels wi h F ⇠1. R o
ph,HXOice is simila o Eq. (2) bu ng and
FUV a e eplaced by he abundance o dus g ains and he ime-
a e aged lux along a s eamline, F ⇥FCRUV, espec i ely. On
he e alua ion o Eq. (5), ✓H2Owas se o be 0.35 (i.e., he es o
he ice man le consis s o o he species), which comes om he
a e age ac ion o H2O in he opmos ⇠50 MLs o he ice man-
le a he onse o collapse (c . Fig. 2). Tha is smalle han he
a e age ac ion o H2O in he en i e ice man le, ⇠0.5, bu la ge
han he su ace co e age o H2O ice, ⇠0.2. The pa ame e bjis
he b anching a io o each ou come jo H2O ice pho odissoci-
a ion (A asa e al. 2015). I is clea ha he pho odissocia ion o
H2O ice is much mo e impo an o H2O ice des uc ion han
pho odeso p ion. Gi en he wa m empe a u e o he p o os ella
en elope (&20–30 K, see Fig. 1), which educes he p obabili y
o hyd ogena ion on he g ain su ace upon H a om adso p ion,
he e o ma ion o H2O ice is no e icien enough o compensa e
o i s pho odissocia ion. Howe e , conside ing he nume ical
da a a e (well) abo e he ed line, he e o ma ion o H2O ice is
no negligible. The sca e in he H2O ice abundance a he high
luence egime likely comes om he di↵e ence in he dus em-
pe a u e when wa e ice is (pa ly) e o med. The e o ma ion o
H2O ice ia OHice +Hice compe es wi h he o ma ion o CO2ice
ia OHice +COice, he la e o which becomes mo e a o able
wi h inc easing dus empe a u e. A highe dus empe a u es
(&40–50 K), whe e su ace chemis y is ine icien , gaseous O2
is he dominan p oduc o wa e ice des uc ion, which o ms
ia he neu al-neu al eac ion in he gas phase, OH +O (see
also D ozdo skaya e al. 2016;Taque e al. 2016).
The HDO ice abundance and he HDO/H2O ice a io show
mo e complex beha io : hey s a o d op a F ⇠100, while
in he highe luence egime, whe e H2O ice s a s o be la gely
des oyed and pa ly e o med, he HDO ice abundance and he
HDO/H2O ice a io end o s ay cons an o inc ease wi h he
luence. The o me indica es again ha he HDO ice abun-
dance is mo e sensi i e o he pho ochemis y han ha o H2O
ice; he uppe ice laye s whe e mos HDO is p esen a e los
p io o he lowe ice laye s whe e mos H2O is p esen . The ed
line in he middle panel shows Eq. (5) o HDO wi h ✓HDO o
2⇥103(c . Fig. 2). The line ep oduces he nume ical da a a
F .200. The beha io o he HDO ice abundance in he highe
1 10 100 1000
10-5
10-4
H2O ice [nH]
1 10 100 1000
10-9
10-8
10-7
10-6
10-5
HDO ice [nH]
1 10 100 1000
No malized FUV luence
10-6
10-4
10-2
1
102
Abundance a io
(D2O/HDO)/(HDO/H2O)
HDO/H2O
D2O/H2O
Fig. 7. H2O ice ( op) and HDO ice (middle) abundances in he luid
pa cels ha a e loca ed in he disk a = acc as unc ions o he
no malized UV luence. The bo om panel shows HDO/H2O ice a io
(black), D2O/H2O ice a io (ligh g ay), and he a io o D2O/HDO o
HDO/H2O ice a io (g ay). Only he luid pa cels in which he H2O ice
abundance is la ge han 105a e plo ed. The blue and ed dashed lines
depic he expec ed H2O (o HDO) ice abundance when only pho odes-
o p ion is an allowed chemical p ocess and when only pho odissocia-
ion and pho odeso p ion a e included, espec i ely. See he main ex
o mo e de ails.
luence egime indica es ha he le el o deu e ium ac iona ion
in e o med wa e ice is simila o o highe han ha in he o igi-
nal wa e ice (i.e., wa e ice be o e he des uc ion). This implies
ha using he HDO/H2O a io as a p obe o he p es ella inhe -
i ance o H2O is limi ed because he HDO/H2O a io does no
enable a dis inc ion be ween he o iginal and e o med ice. Al-
e na i ely, in he bo om panel o Fig. 7, i is seen ha he a io
o D2O/HDO o HDO/H2O is di↵e en be ween he o iginal and
e o med wa e ice. This implies ha he a io o D2O/HDO o
HDO/H2O is a be e p obe o he p es ella inhe i ance o H2O
han solely he HDO/H2O a io. We discuss his p obe o he
p es ella inhe i ance in mo e de ail in Sec . 6.1.
The a ionale o he high HDO/H2O a io in he e o med
wa e ice is wo old: i s , he pho o agmen s a e highly en-
iched in deu e ium as he o iginal ice was highly en iched in
deu e ium, and, second, i akes some ime o he pho o ag-
men s o each he equilib ium le el (i.e., low le el) o deu e ium
ac iona ion a he wa m empe a u es o he en elope ia gas-
phase ion-neu al chemis y. Then, i he imescale o ice e -
o ma ion is sho e han he elaxa ion imescale o deu e ium
ac iona ion, he ac iona ion in he pho o agmen s (i.e., he
o iginal ice) is ans e ed o he e o med ice. This is he case in
ou model. Addi ionally he e a e pa hways o deu e ium ac-
iona ion in he gas phase ha can wo k e en a wa m gas em-
pe a u es, e.g., OH +D!OD +H+810 K (Milla e al. 1989;
A40, page 8 o 18
UV luence = e olu ion
UV
Fu uya e al. 2017
• Need D2O o be su e abou
inhe i ance!
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
A24, page 7 o 57
H2O
HDO
D2O
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
A24, page 7 o 57
H2O
E. F. an Dishoeck e al.:WISH: physics and chemis y om cloud o disks p obed by He schel spec oscopy
s-D2O
H2
O, O H , H2
O
CR, H2
Ice
Low-T
H2D+
H3+
DCO+
HD2+
D3+
Ds-D
s-HDO
Deso p ion
F eeze-ou
D, OD
CO
CO
ee
e
H2
H2
HD
HD
H3+
HDO
D2O
H2O
H2D+, HD2+
E olu ion
G ain
H2O-domina ed ice
Low HDO
High HDO, D2O
CO-domina ed ice
Fig. 5. Simpli ied eac ion ne wo k illus a ing he impo an eac ions
in he deu e a ion o wa e and o he molecules. The le -hand side illus-
a es he cold gas-phase chemis y, leading o high ac iona ion o
gaseous H2D+and a omic D, and ul ima ely gaseous HDO and D2O.
The igh -hand side illus a es how his enhanced D ends up on he ice
and leads o enhanced solid HDO and D2O. The bo om ca oon shows
he di e en ice laye s on a g ain: he H2O-domina ed laye o med
ea ly in he cloud e olu ion wi h low HDO/H2O<103, and he CO-
domina ed laye o med a highe densi ies which is ich in deu e a ed
wa e , wi h D2O/HDO>>HDO/H2O(Fu uya e al. 2015).
o wa e as he wo-phase simple SWaN models do, bu di e -
ences in absolu e wa e abundances can be in oduced because
mul ilaye in e s ella ices a e inhomogenous.
To compa e models wi h obse a ions, no jus he wa e
chemis y bu also he wa e exci a ion and adia i e ans e
need o be ea ed co ec ly. The a ious me hods and model-
ing app oaches adop ed by WISH a e desc ibed in Sec . 4.4 and
Appendix F.
3.3. Wa e deu e a ion
Deu e a ed wa e , HDO and D2O, is o med h ough he same
p ocesses as shown in Fig. 4bu he e a e a numbe o chemical
eac ions ha can enhance he HDO/H2O and D2O/H2O a ios
by o de s o magni ude compa ed wi h he o e all [D]/[H] a io
o 2.0⇥105 ound in he local in e s ella medium (P odano i´
c
e al. 2010). De ails can be ound in Taque e al. (2014) and
Fu uya e al. (2016), and in Cecca elli e al. (2014) o deu e ium
ac iona ion in gene al (see also Sec . 7.3). The p ocesses a e
illus a ed in Fig. 5. The mos e ec i e wa e ac iona ion
occu s on g ains, due o he ac ha he ela i e numbe o
D a oms landing om he gas on he g ain is enhanced com-
pa ed wi h ha o H a oms. In o he wo ds, a omic D/H in cold
gas is much highe han he o e all [D]/[H] a io (Tielens 1983;
Robe s e al. 2003). This high D/H a io landing on g ains na -
u ally leads o enhanced o ma ion o OD, HDO and D2O ice
acco ding o he g ain-su ace o ma ion ou es.
The high a omic D/H a io in he gas, in u n, a ises om he
well-known ac iona ion eac ions ini ia ed by he H+
3+ HD !
H2D++H
2 eac ion, which is exoe gic by ⇠230 K and is hus
e y e ec i e a low empe a u es 25 K (e.g., Wa son 1976;
Aikawa & He bs 1999;S a k e al. 1999;Sipilä e al. 2015). The
H2D+abundance is u he enhanced when he o ho-H2abun-
dance d ops (p e en ing he back eac ion) and when he main
H+
3and H2D+des oye , CO, eezes ou on he g ains (Pagani
e al. 1992,2009;Robe s e al. 2003;Sipilä e al. 2010). The la -
e p ocesses become mo e impo an as he cloud e ol es om
a lowe densi y o a highe densi y phase (Da ois e al. 2003;
Pagani e al. 2013;B ünken e al. 2014;Fu uya e al. 2015). Dis-
socia i e ecombina ion o H2D+and o he ions such as HD+
2,
D+
3and DCO+wi h elec ons hen p oduces enhanced a omic
D which ge s inco po a ed in he ices (Fig. 5). As a esul , he
ou e ice laye s, which a e p oduced when he cloud is dense
and colde , ha e highe HDO/H2O a ios – by o de s o magni-
ude – han he inne laye s and he bulk o he ice. The enhanced
H2D+also leads o enhanced H2DO+and hus HDO in cold gas,
which may play a ole a he lowe densi y edge o he cloud.
Ano he cha ac e is ic o his laye ed ice chemis y is ha he
D2O/HDO a io is much highe han he HDO/H2O a io (Fu uya
e al. 2016). Mo eo e , he deu e a ion o o ganic molecules
o med h ough hyd ogena ion o CO ice in he la e cloud s ages
is gene ally much highe han ha o wa e (Cazaux e al. 2011;
Taque e al. 2014;Fu uya e al. 2016).
The deso p ion p ocesses – pho odeso p ion a low ice em-
pe a u es (Öbe g e al. 2009;A asa e al. 2015;C uz-Diaz
e al. 2018) and he mal deso p ion a high ice empe a u es –
ha e a small o negligible e ec on he deu e ium ac iona-
ion. In o he wo ds, he gaseous HDO/H2O and D2O/H2O a ios
should e lec he ice a ios ollowing deso p ion i no subse-
quen gas-phase eac ions a e in ol ed. I is impo an o no e
ha pho odeso p ion is only e ec i e in he ou e ew laye s o
he ice, whe eas he mal deso p ion emo es he bulk ice man-
le. This selec i e o ma ion and emo al o ice laye s u ns ou
o be impo an in he in e p e a ion o HIFI obse a ions o
HDO/H2O a ios in cold e sus wa m gas.
In wa m gas, he exchange eac ion D + OH !H + OD is
likely ba ie less and can be e ec i e in enhancing OD, espe-
cially since he e e se eac ion seems o ha e a ba ie o a ound
800 K (Thi e al. 2010). Pho odissocia ion o HDO can also
enhance OD compa ed wi h OH by a ac o o 2–3, which could
be a ou e o u he ac iona ion. Finally, in high empe a u e
gas in disks he exchange eac ion H2O + HD $HDO + H2is
o en included. Simila ly, he e a e eac ions inside he ices ha
can bo h enhance and educe he wa e ac iona ion (Lambe s
e al. 2015,2016) bu a e no conside ed he e (see discussion in
Fu uya e al. 2016).
4. He schel wa e spec a and maps
In his sec ion, we b ie ly summa ize he main ea u es cha ac-
e izing wa e emission obse ed wi h He schel, la gely based on
WISH+ p og ams. Figu e 2illus a es he complexi y o indi id-
ual wa e p o iles o p o os a s obse ed wi h HIFI o e mo e
han ±50 km s1whe eas Fig. 6shows he spa ial dis ibu ion
imaged wi h PACS. Figu e 7p esen s examples o ull spec al
scans wi h PACS wi h many lines de ec ed. The main conclu-
sion om he combined analysis o he wa e maps, he b oad
wa e line p o iles, and i s exci a ion, is ha mos o he obse ed
gaseous wa e is uni e sally associa ed wi h wa m ou lowing
and shocked gas o se e al hund ed K. All wa e lines obse ed
by He schel wi hin WISH show he mal emission, so nonmas-
ing, in con as wi h he 22 GHz mase o en associa ed wi h
s a - o ming egions. A leas wo di e en ypes o kinema ic
componen s a e in ol ed, wi h wa e being a signi ican (bu no
necessa ily dominan ) coolan . In con as , wa e emission is no
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H2O
HDO
D2O