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The [D/H] abundance de i ed om p o os ella ou flows
ac oss he Galac ic disk measu ed wi h JWST
Read he
pape he e!
Logan F ancis
Deu e ium and Galac ic Chemical E olu ion
●P imo dial D c ea ed in Big Bang,
only deple ed in s ella in e io s
D + p → 3He + γ
●BBN models indica e p imo dial
[D/H] o 2.58 ± 0.13 × 10-5, in good
ag eemen wi h obse a ional
cons ain s (Cybu + 2016)
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Mixing and
inhomogenei y?
●Models o Galac ic chemical
e olu ion gene ally p edic
[D/H] o dec ease owa ds he
Galac ic cen e
P imo dial [D/H]
How can we measu e [D/H]?
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T ace Complex Deu e a ed
Molecules, e.g. DCN/HCN
ISM D I and H I
abso p ion lines
HD and H2
Example
s udies
Penzias e al. 1977, 1979 Linsky e al. 2006,
P odano ić e al. 2010
Neu eld e al. 2006,
Yuan e al. 2012
𝝺sub-mm/ adio (g ound) UV (space) mid-IR/ a -IR (space)
P os Ro a ional ansi ions easily
de ec able in g ound-based
obse a ions
Di ec compa ison o H
and D
Nea ly di ec
measu emen o [D/H]
Simple chemical
ac iona ion
Cons Highly unce ain due o complex
chemical ac iona ion
Blending wi h O I lines
Sa u a ed a la ge
dis ances
Weak emission lines
Bu is some Deu e ium locked up in g ains?
●C-D bond much s onge han C-H
bond → D can be e icien ly locked up
in PAHs and ca bonaceous dus g ains
(Ju a 1982, Tielens 1983, D aine 2006).
●Sca e in [D/H] om UV abso p ion
lines ou side local bubble a gued o be
due o a ying deple ion o D in o dus
g ains (Linksy e al. 2006)
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log(105 [D/H])
local
bubble
non-local
bubble
P odano ić e al. 2010
P imo dial [D/H] = 2.58 x 10-5
LB median ~ 1.6 x 10 -5
De ec ion o deu e a ed PAHs wi h JWST
●Deu e a ed PAHs can accoun o a la ge
ac ion o ‘missing’ D (D aine e al 2006)
●O ion ba obse ed alipha ic NPAD/NPAH ~3%
(Pee e s e al. 2024)
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PADs, 4.646 mic on alipha ic bond
Measu ing [D/H] wi h JWST/MIRI
●H2 and HD ha e many ansi ions in JWST MIRI/MRS ange (4.9-28 mic on)
●Las acili ies capable o his we e Spi ze and ISO - huge sensi i i y
imp o emen s wi h JWST
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Obse a ions o p o os a s ac oss he Galac ic disk
●MIRI/MRS obse a ions o 5 low-mass, nea by p o os a s + 5
high-mass, dis an a ge s om he JOYS p og ams (1290, 1257)
●All a ge s ha e H2 b igh ou flows. Low-mass ou flows esol ed a e
spa ially well- esol ed.
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Line Momen maps: HH 211
B igh es HD emission in
sample loca ed owa ds
s ong shock kno s aced
by [Fe I], [Fe II], [S I],
H2 S(7)
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Measu ing [D/H] om HD and H2
●Ex ac spec a owa ds posi ions wi h b igh H2 and
cons uc o a ion diag ams o H2 and HD
●Ex inc ion, H2 o ho- o-pa a a io, included as ee
pa ame e s in fi
●Calcula e [D/H] abundance om HD and wa m H2 column
densi y: [D/H] = 1/2 x NHD x HDco / NH2,wa m
●Co ec ion ac o HDco akes in o accoun sub he mal
exci a ion and con e sion o HD → D in shocks
(Be oldi +1999)
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HD column densi y co ec ion ac o
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HDco includes:
●Chemical con e sion o HD o D:
●Sub- he mal exci a ion o HD (n < nc i ~ 106 cm-3)
E ec s wo k in opposi e di ec ions - combined
e ec is is app oxima ely cons an ac oss a wide
ange o shock condi ions wi h HDco = 2.54
(Be oldi+1999)
hemal
sub- he mal
HD column densi y co ec ion ac o
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HDco includes:
●Chemical con e sion o HD o D:
●Sub- he mal exci a ion o HD (n < nc i ~ 106 cm-3)
E ec s wo k in opposi e di ec ions - combined
e ec is is app oxima ely cons an ac oss a wide
ange o shock condi ions wi h HDco = 2.54
(Be oldi+1999)
Ro a ion Diag am and [D/H] Resul s
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Measu ing [D/H] wi h JWST/MIRI
●Bo h H2 and HD ha e mul iple ansi ions in JWST MIRI/MRS ange
(4.9-28 mic on)
●Las acili ies capable o his we e Spi ze and ISO - huge sensi i i y
imp o emen s wi h JWST
ISO (1995-1998) Spi ze (2003-2009) JWST (2021-P esen )
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[D/H] a ia ions in ou Galaxy
Models o Galac ic chemical e olu ion gene ally p edic [D/H] o dec ease
owa ds he Galac ic cen e :
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Romano e al. 2006
an de Voo e al. 2018
Addi ional momen maps: IRAS 23385, IRAS 18089
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