Chemical properties of the most
massive evolved stars
G. Quintana-Lacaci1, J. Cernicharo1, C. Sánchez-Contreras1, L.Velilla1,
V.Bujarrabal2, J. Alcolea2, A. Castro-Carrizo3, D. Teyssier4, L. Decin5, J.
Pearson6
CAB (INTA-CSIC), 2OAN (IGN), 3IRAM, 4ESAC, 5KUL, 6JPL
1
Sevilla 2012
What do we know? Molecular Emisison
- RSGs
VY Cma
NaCl, PN, HNC, HCO+, AlO, AlOH,...
( Tenenbaum & Zyuris, 2010)
NML Cyg, Betelgeuse
CO (low-J, high-J), OH, H2O,
SO, SiO, NH3, H2S,... (Teyssier et al. 2012)
S Per, PZ Cas, µ Cep
Low-J CO lines
(Quintana-Lacaci et al. In prep)
- YHGs
IRC+10420 , AFGL 2343
CS, HCN, HNC, CN, SiS, SiO, HCO+,...
(Quintana-Lacaci et al. 2007)
What do we know?
Structure:
- RSGs
NML Cyg
VY Cma
Betelgeuse
S Per
PZ Cas
µ Cep
spherical + outflows ??
spherical + outflows (Muller et al. 2006)
spherical (Castro-Carrizo et al.)
spherical (Quintana-Lacaci et al. prep)
hourglass (Quintana-Lacaci et al.prep)
hourglass ??
- YHGs
IRC+10420 , AFGL 2343
Spherical + shocks
(Castro-Carrizo et al. 2007, Quintana-Lacaci et al. 2008)
What do we expect?
C/O ratio
Chemistry:
a) CNO + HBB + dredge up
M* < 1.4 M⊙
1.5 M⊙ < M*< 3 M⊙
3 M⊙ < M *
b) NeNa cycle
O-rich and N-rich chemistry
O-rich chemistry
C-rich chemistry
N-rich chemistry
K, Mg, Na
c) Shock-induced chemistry
d) Photo-induced chemistry for YHGs
Chemistry in the RSGs: VY CMa
Best studied RGS
NaCl, PN, HNC, HCO+, AlO, AlOH,...
( Tenenbaum & Zyuris, 2010)
Muller et al. 2007
Chemistry in the RSGs: VY CMa
IRAM 30m Radiotelescope:
Band
Freqs (GHz)
Status
3mm
83 – 117
Ongoing
2mm
129 – 174
Ongoing
1mm
202 – 274
Ongoing
0.8mm
277 – 358
Ongoing
HIFI
Band
Freqs (GHz)
Band
Freqs (GHz)
1b
554.5 – 636.5
5a
1108.1 – 1224.0
2a
626.0 – 726.0
6a
1446.2 – 1562.9
3a
799.0 – 856.0
6b
1573.4 – 1702.9
4a
949.0 – 1060.0
7a
1696.4 – 1798.9
4b
1046.6 – 1122.0
7b
1788.5 – 1906.9
Chemistry in the RSGs: VY CMa
Chemistry in the RSGs: VY CMa
Chemistry in the RSGs: VY CMa
Chemistry in the RSGs: VY CMa
~ 1200 lines
52 species identified
12
CO, 13CO, C18O
H2O, H218O, H217O, OH
SiO, 30SiO, 29SiO, Si17O, Si18O
SO2, 34SO2, 33SO2, SO18O, SO17O
NaCl, Na37Cl
NS, NH3
AlO, AlOH, AlCl
HCO+,CH3OH,
CS, TiO
SO, 34SO, 33SO
SiS, 30SiS,
29
SiS, Si34S, Si33S, SiN
PN, PO, CCP, 13CCP
HCl, H37Cl
HCN, H13CN, HNC, CN
H2CO, H2C18O
H2S, H233S
Chemistry in the YHGs: IRC+10420
Prototypical YHG star
1D LVG already used to model IRC+10420
Emission
(Teyssier, Quintana-Lacaci et al. 2012)
CS, HCN, HNC, CN, SiS, SiO, HCO+,...
(Quintana-Lacaci et al. 2007)
Chemistry in the YHGs: IRC+10420
Prototypical YHG star
1D LVG already used to model IRC+10420
Emission
(Teyssier, Quintana-Lacaci et al. 2012)
CS, HCN, HNC, CN, SiS, SiO, HCO+,...
(Quintana-Lacaci et al. 2007)
No refractory
materials
Chemistry in the YHGs: IRC+10420
IRAM 30m Radiotelescope:
Band
Freqs (GHz)
Status
3mm
83 – 116.3
reduced
1mm
199.1 – 258.8
reduced
Band
Freqs (GHz)
Status
2mm
202 – 274
Granted
0.8mm
277 – 358
Granted
HIFI
CO, H2O, OH, 13CO, NH3
Chemistry in the YHGs: IRC+10420
Chemistry in the YHGs: IRC+10420
Chemistry in the YHGs: IRC+10420
12
CO, 13CO, C18O, H2O
SO, 34SO, SO2
SiO, 30SiO, 29SiO, SiS, 29SiS
CS, C2S
HCN, H13CN, HNC, HC3N , CN
HCO+
N2H+
CH3OH
NO, NS, PN
NH3, OH
NO, N2H+ OH+231.8
L. Velilla Poster
C-rich Massive stars?
C-rich stars with high expansion velocity (HVC stars)
High expasion velocity
High luminosity
Dust to gas ratio
High HCN abundance
C-rich + N-rich
Maser
Marigo (2008) Under certain conditions HBB stops!!
C abundance will raise again
These objects might exist
C-rich Massive stars? Structure
IRC+10401
AFGL2233
C-rich Massive stars? Structure
AFGL2233
HVC
AFGL2343
YHG
HVCs
Conclusions
- Massive evolved stars show extremely rich chemistry.
IRC+10420: O-rich, N-rich, Shocks, PDR
VY Cma: O-rich, N-rich, Shocks, Grain formation zone
HVCs: C-rich, N-rich
O-rich
-
C-rich
Conclusions
- Massive evolved stars show extremely rich chemistry.
IRC+10420: N-rich, Shocks, PDR
VY Cma: O-rich, N-rich, Shocks, Grain formation zone
HVCs: C-rich, N-rich
O-rich
N-rich
C-rich