©B. Ta eshi / ESO
Sagi a ius B2(N), a goldmine o in es iga e
he o ma ion o complex o ganic molecules
A naud Belloche
Max-Planck-Ins i u ¨
u Radioas onomie
Towa ds new on ie s: he as ochemical jou ney
om young s ella nu se ies o exoplane s
Ga ching, Ge many
11 Ma ch 2025
ü Radioas onomie
Max-Planck-Ins i u
2 / 12
In memo y o Ka l Men en (1957–2024)
IKa l o iginally mo i a ed he Sg B2 spec al line su eys a MPI R
Iwe deeply miss his en husiasm, his scien i ic cu iosi y and c ea i i y,
as well as his open and gene ous pe sonali y
Icon e ence a Wasem Klos e
Engel hal, Ge many
IAugus 18-22, 2025
Is a o ma ion and e olu ion,
on bo h local and global scales
2 / 12
In memo y o Ka l Men en (1957–2024)
IKa l o iginally mo i a ed he Sg B2 spec al line su eys a MPI R
Iwe deeply miss his en husiasm, his scien i ic cu iosi y and c ea i i y,
as well as his open and gene ous pe sonali y
Icon e ence a Wasem Klos e
Engel hal, Ge many
IAugus 18-22, 2025
Is a o ma ion and e olu ion,
on bo h local and global scales
3 / 12
The high mass s a - o ming egion Sg B2
Cen al Molecula Zone a 870 µm
(ATLASGAL/LABOCA + Planck ©MPI R/A. Weiß)
Sg B2(N) in he mal dus emission
a 850 µm (SMA, Qin+ 2011)
Ione o he mos p ominen s a - o ming
egions in ou Galaxy
Icon ains wo dense clumps (N and M) ha
hos p o oclus e s (ho co es, UC H II egions)
Sg B2(N)
I wo main ho co es (N1 and N2)
(+ ain e ones: Bon and+ 2017, S´
anchez-Monge+ 2017)
Ihigh column densi ies
(NH2∼1024–1025 cm−2o e ew a csec)
⇒key ad an age o de ec ion o complex
o ganic molecules (COMs)
3 / 12
The high mass s a - o ming egion Sg B2
Cen al Molecula Zone a 870 µm
(ATLASGAL/LABOCA + Planck ©MPI R/A. Weiß)
Sg B2(N) in he mal dus emission
a 850 µm (SMA, Qin+ 2011)
Ione o he mos p ominen s a - o ming
egions in ou Galaxy
Icon ains wo dense clumps (N and M) ha
hos p o oclus e s (ho co es, UC H II egions)
Sg B2(N)
I wo main ho co es (N1 and N2)
(+ ain e ones: Bon and+ 2017, S´
anchez-Monge+ 2017)
Ihigh column densi ies
(NH2∼1024–1025 cm−2o e ew a csec)
⇒key ad an age o de ec ion o complex
o ganic molecules (COMs)
3 / 12
The high mass s a - o ming egion Sg B2
Cen al Molecula Zone a 870 µm
(ATLASGAL/LABOCA + Planck ©MPI R/A. Weiß)
Sg B2(N) in he mal dus emission
a 850 µm (SMA, Qin+ 2011)
Ione o he mos p ominen s a - o ming
egions in ou Galaxy
Icon ains wo dense clumps (N and M) ha
hos p o oclus e s (ho co es, UC H II egions)
Sg B2(N)
I wo main ho co es (N1 and N2)
(+ ain e ones: Bon and+ 2017, S´
anchez-Monge+ 2017)
Ihigh column densi ies
(NH2∼1024–1025 cm−2o e ew a csec)
⇒key ad an age o de ec ion o complex
o ganic molecules (COMs)
4 / 12
(Re)Explo ing Molecula Complexi y wi h ALMA
Ispec al line su eys o Sg B2(N) o e 84 – 114 GHz wi h ALMA
in cycles 0/1 (EMoCA, esolu ion 1.600 ; Belloche+ 2016)
and cycle 4 (ReMoCA, 0.600 ; Belloche+ 2019)
I ollow-up o ou success ul su ey wi h IRAM 30 m elescope
(Belloche+ 2008, 2009, 2013)
Imain goals: unde s and he g ow h o molecula complexi y in he ISM,
sea ch o new COMs, es as ochemical models (collabo a ion wi h R. Ga od)
Inew COMs de ec ed wi h EMoCA/ReMoCA (collabo a ion wi h spec oscopis s):
i-C3H7CN,CH3NHCHO,NH2C(O)NH2,i-C3H7OH (Belloche+ 2014, 2017, 2019, 2022)
I his alk: insigh s in o chemical di e en ia ion om he molecula
composi ion o ho co es in Sg B2(N2)
(Belloche, Ga od, M¨
ulle , Mo in, Willis, & Men en, a icle ecen ly submi ed o A&A)
4 / 12
(Re)Explo ing Molecula Complexi y wi h ALMA
Ispec al line su eys o Sg B2(N) o e 84 – 114 GHz wi h ALMA
in cycles 0/1 (EMoCA, esolu ion 1.600 ; Belloche+ 2016)
and cycle 4 (ReMoCA, 0.600 ; Belloche+ 2019)
I ollow-up o ou success ul su ey wi h IRAM 30 m elescope
(Belloche+ 2008, 2009, 2013)
Imain goals: unde s and he g ow h o molecula complexi y in he ISM,
sea ch o new COMs, es as ochemical models (collabo a ion wi h R. Ga od)
Inew COMs de ec ed wi h EMoCA/ReMoCA (collabo a ion wi h spec oscopis s):
i-C3H7CN,CH3NHCHO,NH2C(O)NH2,i-C3H7OH (Belloche+ 2014, 2017, 2019, 2022)
I his alk: insigh s in o chemical di e en ia ion om he molecula
composi ion o ho co es in Sg B2(N2)
(Belloche, Ga od, M¨
ulle , Mo in, Willis, & Men en, a icle ecen ly submi ed o A&A)
4 / 12
(Re)Explo ing Molecula Complexi y wi h ALMA
Ispec al line su eys o Sg B2(N) o e 84 – 114 GHz wi h ALMA
in cycles 0/1 (EMoCA, esolu ion 1.600 ; Belloche+ 2016)
and cycle 4 (ReMoCA, 0.600 ; Belloche+ 2019)
I ollow-up o ou success ul su ey wi h IRAM 30 m elescope
(Belloche+ 2008, 2009, 2013)
Imain goals: unde s and he g ow h o molecula complexi y in he ISM,
sea ch o new COMs, es as ochemical models (collabo a ion wi h R. Ga od)
Inew COMs de ec ed wi h EMoCA/ReMoCA (collabo a ion wi h spec oscopis s):
i-C3H7CN,CH3NHCHO,NH2C(O)NH2,i-C3H7OH (Belloche+ 2014, 2017, 2019, 2022)
I his alk: insigh s in o chemical di e en ia ion om he molecula
composi ion o ho co es in Sg B2(N2)
(Belloche, Ga od, M¨
ulle , Mo in, Willis, & Men en, a icle ecen ly submi ed o A&A)
7 / 12
Chemical composi ion: co ela ions and ou lie s
Composi ion:
Iup o 24 COMs de ec ed
Co ela ions:
I igh co ela ion AN02/AN03
Igood co ela ion N2b/AN06 bu
p ominen ou lie s NH2CHO and HNCO
Classes o molecule: O, O+N,N,C,S
IAN03: poo e co ela ion o S-bea ing
con en wi h o he sou ces
IAN06: unde abundan O+N-bea ing
species
7 / 12
Chemical composi ion: co ela ions and ou lie s
Composi ion:
Iup o 24 COMs de ec ed
Co ela ions:
I igh co ela ion AN02/AN03
Igood co ela ion N2b/AN06 bu
p ominen ou lie s NH2CHO and HNCO
Classes o molecule: O, O+N,N,C,S
IAN03: poo e co ela ion o S-bea ing
con en wi h o he sou ces
IAN06: unde abundan O+N-bea ing
species
7 / 12
Chemical composi ion: co ela ions and ou lie s
Composi ion:
Iup o 24 COMs de ec ed
Co ela ions:
I igh co ela ion AN02/AN03
Igood co ela ion N2b/AN06 bu
p ominen ou lie s NH2CHO and HNCO
Classes o molecule: O, O+N,N,C,S
IAN03: poo e co ela ion o S-bea ing
con en wi h o he sou ces
IAN06: unde abundan O+N-bea ing
species
7 / 12
Chemical composi ion: co ela ions and ou lie s
Composi ion:
Iup o 24 COMs de ec ed
Co ela ions:
I igh co ela ion AN02/AN03
Igood co ela ion N2b/AN06 bu
p ominen ou lie s NH2CHO and HNCO
Classes o molecule: O, O+N,N,C,S
IAN03: poo e co ela ion o S-bea ing
con en wi h o he sou ces
IAN06: unde abundan O+N-bea ing
species
7 / 12
Chemical composi ion: co ela ions and ou lie s
Composi ion:
Iup o 24 COMs de ec ed
Co ela ions:
I igh co ela ion AN02/AN03
Igood co ela ion N2b/AN06 bu
p ominen ou lie s NH2CHO and HNCO
Classes o molecule: O, O+N,N,C,S
IAN03: poo e co ela ion o S-bea ing
con en wi h o he sou ces
IAN06: unde abundan O+N-bea ing
species
7 / 12
Chemical composi ion: co ela ions and ou lie s
Composi ion:
Iup o 24 COMs de ec ed
Co ela ions:
I igh co ela ion AN02/AN03
Igood co ela ion N2b/AN06 bu
p ominen ou lie s NH2CHO and HNCO
Classes o molecule: O, O+N,N,C,S
IAN03: poo e co ela ion o S-bea ing
con en wi h o he sou ces
IAN06: unde abundan O+N-bea ing
species
8 / 12
Radicals: s ingen uppe limi s o models
×model p edic ions
(MAGICKAL, Ga od+ 2022)
ICH2CHO,CH2CN,C3N,NH2CO o e p oduced by he model
⇒lack o app op ia e des uc ion mechanisms in he ne wo k,
in pa icula eac ions wi h a omic hyd ogen (which he o he adicals ha e)
8 / 12
Radicals: s ingen uppe limi s o models
×model p edic ions
(MAGICKAL, Ga od+ 2022)
ICH2CHO,CH2CN,C3N,NH2CO o e p oduced by he model
⇒lack o app op ia e des uc ion mechanisms in he ne wo k,
in pa icula eac ions wi h a omic hyd ogen (which he o he adicals ha e)
8 / 12
Radicals: s ingen uppe limi s o models
×model p edic ions
(MAGICKAL, Ga od+ 2022)
ICH2CHO,CH2CN,C3N,NH2CO o e p oduced by he model
⇒lack o app op ia e des uc ion mechanisms in he ne wo k,
in pa icula eac ions wi h a omic hyd ogen (which he o he adicals ha e)
8 / 12
Radicals: s ingen uppe limi s o models
×model p edic ions
(MAGICKAL, Ga od+ 2022)
ICH2CHO,CH2CN,C3N,NH2CO o e p oduced by he model
⇒lack o app op ia e des uc ion mechanisms in he ne wo k,
in pa icula eac ions wi h a omic hyd ogen (which he o he adicals ha e)
11 / 12
Chemical di e en ia ion by class o molecule
I igh co ela ion wi h G31.41 and IRAS16293B a e no malizing
by class o molecule
Ipoo co ela ion wi h G+0.693, due o N-bea ing molecules;
S-bea ing species mo e p ominen in G+0.693
Ino co ela ion wi h TMC-1
Ila ges a iance: N-bea ing class
( om igh co ela ion o no co ela ion; o e all shi s w. . o he classes)
Ismalles a iance: S-bea ing class
( igh co ela ion wi h G31.41, IRAS16293B, G+0.693; good co ela ion wi h TMC-1)
11 / 12
Chemical di e en ia ion by class o molecule
I igh co ela ion wi h G31.41 and IRAS16293B a e no malizing
by class o molecule
Ipoo co ela ion wi h G+0.693, due o N-bea ing molecules;
S-bea ing species mo e p ominen in G+0.693
Ino co ela ion wi h TMC-1
Ila ges a iance: N-bea ing class
( om igh co ela ion o no co ela ion; o e all shi s w. . o he classes)
Ismalles a iance: S-bea ing class
( igh co ela ion wi h G31.41, IRAS16293B, G+0.693; good co ela ion wi h TMC-1)
11 / 12
Chemical di e en ia ion by class o molecule
I igh co ela ion wi h G31.41 and IRAS16293B a e no malizing
by class o molecule
Ipoo co ela ion wi h G+0.693, due o N-bea ing molecules;
S-bea ing species mo e p ominen in G+0.693
Ino co ela ion wi h TMC-1
Ila ges a iance: N-bea ing class
( om igh co ela ion o no co ela ion; o e all shi s w. . o he classes)
Ismalles a iance: S-bea ing class
( igh co ela ion wi h G31.41, IRAS16293B, G+0.693; good co ela ion wi h TMC-1)
11 / 12
Chemical di e en ia ion by class o molecule
I igh co ela ion wi h G31.41 and IRAS16293B a e no malizing
by class o molecule
Ipoo co ela ion wi h G+0.693, due o N-bea ing molecules;
S-bea ing species mo e p ominen in G+0.693
Ino co ela ion wi h TMC-1
Ila ges a iance: N-bea ing class
( om igh co ela ion o no co ela ion; o e all shi s w. . o he classes)
Ismalles a iance: S-bea ing class
( igh co ela ion wi h G31.41, IRAS16293B, G+0.693; good co ela ion wi h TMC-1)
11 / 12
Chemical di e en ia ion by class o molecule
I igh co ela ion wi h G31.41 and IRAS16293B a e no malizing
by class o molecule
Ipoo co ela ion wi h G+0.693, due o N-bea ing molecules;
S-bea ing species mo e p ominen in G+0.693
Ino co ela ion wi h TMC-1
Ila ges a iance: N-bea ing class
( om igh co ela ion o no co ela ion; o e all shi s w. . o he classes)
Ismalles a iance: S-bea ing class
( igh co ela ion wi h G31.41, IRAS16293B, G+0.693; good co ela ion wi h TMC-1)
11 / 12
Chemical di e en ia ion by class o molecule
I igh co ela ion wi h G31.41 and IRAS16293B a e no malizing
by class o molecule
Ipoo co ela ion wi h G+0.693, due o N-bea ing molecules;
S-bea ing species mo e p ominen in G+0.693
Ino co ela ion wi h TMC-1
Ila ges a iance: N-bea ing class
( om igh co ela ion o no co ela ion; o e all shi s w. . o he classes)
Ismalles a iance: S-bea ing class
( igh co ela ion wi h G31.41, IRAS16293B, G+0.693; good co ela ion wi h TMC-1)
12 / 12
Conclusions
Ila ge a iance o class o N-bea ing molecules among sou ces
⇒mo e sensi i e han O-bea ing o S-bea ing classes o
Ishocks (G+0.693)
Ilow-T gas-phase chemis y a e non- he mal deso p ion (TMC-1)
Io densi y (G+0.693, TMC-1)
Iseg ega ion be ween O-bea ing and N-bea ing species: pa ial deso p ion
migh encou age p e e en ial elease o ou e ice laye s ha a e ich in CO
and ela ed O-bea ing species while lea ing deepe , N- ich ma e ial in place
→abundance shi s be ween N-bea ing and O-bea ing molecules may
indica e how iolen ly and comple ely he ice man les a e deso bed
Iimp o emen s o chemical models needed o dis inguish be ween ice laye s
beyond he ypical bulk+su ace-laye pa adigm
12 / 12
Conclusions
Ila ge a iance o class o N-bea ing molecules among sou ces
⇒mo e sensi i e han O-bea ing o S-bea ing classes o
Ishocks (G+0.693)
Ilow-T gas-phase chemis y a e non- he mal deso p ion (TMC-1)
Io densi y (G+0.693, TMC-1)
Iseg ega ion be ween O-bea ing and N-bea ing species: pa ial deso p ion
migh encou age p e e en ial elease o ou e ice laye s ha a e ich in CO
and ela ed O-bea ing species while lea ing deepe , N- ich ma e ial in place
→abundance shi s be ween N-bea ing and O-bea ing molecules may
indica e how iolen ly and comple ely he ice man les a e deso bed
Iimp o emen s o chemical models needed o dis inguish be ween ice laye s
beyond he ypical bulk+su ace-laye pa adigm
12 / 12
Conclusions
Ila ge a iance o class o N-bea ing molecules among sou ces
⇒mo e sensi i e han O-bea ing o S-bea ing classes o
Ishocks (G+0.693)
Ilow-T gas-phase chemis y a e non- he mal deso p ion (TMC-1)
Io densi y (G+0.693, TMC-1)
Iseg ega ion be ween O-bea ing and N-bea ing species: pa ial deso p ion
migh encou age p e e en ial elease o ou e ice laye s ha a e ich in CO
and ela ed O-bea ing species while lea ing deepe , N- ich ma e ial in place
→abundance shi s be ween N-bea ing and O-bea ing molecules may
indica e how iolen ly and comple ely he ice man les a e deso bed
Iimp o emen s o chemical models needed o dis inguish be ween ice laye s
beyond he ypical bulk+su ace-laye pa adigm
12 / 12
Conclusions
Ila ge a iance o class o N-bea ing molecules among sou ces
⇒mo e sensi i e han O-bea ing o S-bea ing classes o
Ishocks (G+0.693)
Ilow-T gas-phase chemis y a e non- he mal deso p ion (TMC-1)
Io densi y (G+0.693, TMC-1)
Iseg ega ion be ween O-bea ing and N-bea ing species: pa ial deso p ion
migh encou age p e e en ial elease o ou e ice laye s ha a e ich in CO
and ela ed O-bea ing species while lea ing deepe , N- ich ma e ial in place
→abundance shi s be ween N-bea ing and O-bea ing molecules may
indica e how iolen ly and comple ely he ice man les a e deso bed
Iimp o emen s o chemical models needed o dis inguish be ween ice laye s
beyond he ypical bulk+su ace-laye pa adigm
