Stellar evolution and the ‘O-rich AGB sequence’ F. Jiménez-Esteban 1,2, P. García-Lario 2 & D....
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Transcript of Stellar evolution and the ‘O-rich AGB sequence’ F. Jiménez-Esteban 1,2, P. García-Lario 2 & D....
Stellar evolution and the ‘O-rich AGB sequence’
F. Jiménez-Esteban1,2,
P. García-Lario2 & D. Engels1
1- Hamburger Sterwarte / Universität Hamburg
2- ISO Data Center / European Space Astronomy Center
Well defined location of O-rich AGB stars in the IRAS c-c diagram
Sequence of increasing optical thickness of the CSE:
3 possible interpretations:
- Evolutionary
- Progenitor mass
- Combination of both
AGB PN
Stellar evolution and the ‘O-rich AGB sequence’The ‘O-rich AGB sequence’
van der Veen & Habing, 1988, A&A, 194, 125
Thinner Bluer
Thicker Redder
Stellar evolution and the ‘O-rich AGB sequence’The sample
Two previous photometric analysis of OH/IR stars: I - Arecibo sample - 363 (Jiménez-Esteban et al., 2005, A&A, 431, 779) II - GLMP sample - 94 (Jiménez-Esteban et al., 2005, A&A, submitted)
Samples are not directly comparable, but complementary:
i) Arecibo: blue colours GLMP: red colours
ii) Arecibo: Arecibo sky GLMP: the entire sky (32% of GLMP in the GB)
457 OH/IR stars providing very good coverage
Stellar evolution and the ‘O-rich AGB sequence’Bolometric Flux
Well covered Spectral Energy Distribution J-H-K ( own obs. or 2MASS ); A-C-D-E ( MSX ); 12-25-60-100 ( IRAS ) (1.25 - 1.65 - 2.2 m ) (8.28 - 12.13 - 14.65 - 21.3 m )
Integration: trapezium rule + Extrapolation Fbol
Stellar evolution and the ‘O-rich AGB sequence’Absolute bolometric luminosity
41 GLMP OH/IR in the direction of the Galactic Bulge D 8kpc
bol
2bol FD4L
Wide range 2500 – 26000 L
Maximum in 3500 L
Coincidence with other
authors who studied mainly bluer samples of OH/IR stars in the GB and in the solar neighborhood
We assume LOH/IR 3500 L
Distance & Galactic Height
( Habing et al. 1985; Rowan-Robinson & Chester 1987; Jones et al. 1994; Blommaert et al. 1998; Wood et al. 1998; Jackson et al. 2002; Knauer et al. 2001 )
The luminosity function may be similar throughout theGalaxy and not very dependent on the colours
Stellar evolution and the ‘O-rich AGB sequence’Parametrization
[12] –[25] adequate descriptor for the blue part of the sequence
[25] –[60] adequate descriptor for the red part of the sequence
We parameterize the curve:
0,72-2,42[60]-[25]
Ln0,912[25]-[12]
Lower λ BluerHigher λ Redder
Stellar evolution and the ‘O-rich AGB sequence’Galactic Height
Relation between and the galactic height
red OH/IR stars are concentrated towards the Galactic Plane
The red part of the O-rich AGB sequence mustbe populated mainly with objects of higher mass
Stellar evolution and the ‘O-rich AGB sequence’Expansion velocity
Deficit of OH/IR stars with high vexp at large GH
Systematic trend: high vexp
in OH/IR stars with small GH
Low vexp associated to low
High associated to high vexp
Low OH/IR stars covers the whole range of vexp
The red part of the O-rich AGB sequence is mainly populated by high progenitor mass and high Vexp stars
The blue part of the O-rich AGB sequence is populated by OH/IR stars with a wide range of Vexp and progenitor masses
Stellar evolution and the ‘O-rich AGB sequence’Evolutionary Scenario
Evolutionary ScenarioAll OH/IR stars would start the AGB phase, independent of their progenitor mass, in the blue part of the O-rich AGB sequence, and
then they would evolve toward redder colors, although only the more massive stars would reach the red end of the O-rich AGB sequence.
Stellar evolution and the ‘O-rich AGB sequence’Galactic Scale Height
H
Z
e
0NZ N
∆ = 0.3
Galactic scale height ( H ):
Range
N of stars
H( pc )
Ext. blue 0.6 43 536
Blue 0.6 < 1.2 193 344
Transition 1.2 < 1.8 58 287
Red 1.8 < 3.0 66 193
Ext. red 3.0 < 22 48
Thin CSE
Thin & Thick CSE
Thick CSE
Stellar evolution and the ‘O-rich AGB sequence’Evolutionary connection
Extremely blue ( H = 536 pc )Optical Miras with short-P ( H = 600 pc )(Jura 1994)
Type III PN ( <Z> = 660 pc )(Maciel & Dutra 1992)
Blue ( H = 344 pc )Solar neighbourhood OH/IR ( H = 330 pc )(Ortiz & Maciel 1996)
Miras close to the Galactic Plane ( H = 315 pc )(Wood & Cahn 1977)
Type II PN ( <Z> = 350 pc )(Maciel & Dutra 1992)
Stellar evolution and the ‘O-rich AGB sequence’
Transition ( H = 287 pc )Intermediate- and long-P Miras ( H = 240 pc )(Jura & Kleinmann 1992)
Optical C-rich stars ( H = 290 - 260 pc )(Groenewegen et al. 1992)
( Massive ) Type II PN ( 250 < <Z> < 350 pc )
Red ( H = 193 pc )IR C-stars ( H = 155-200 pc )
(Groenewegen et al. 1992; Claussen et al. 1996)
O-rich HBB AGB stars (N-rich)Type I PN ( <Z> = 150 pc )
(Maciel & Dutra 1992)
Extremely red ( H = 48 pc )Infrared PN? ( OHPNe )
Evolutionary connection
Stellar evolution and the ‘O-rich AGB sequence’Conclusions
Unique sample of ~450 OH/IR to study the O-rich AGB sequence
Found a triple relation among Progenitor mass - - vexp
Postulated an evolutionary scenario which need to be further investigated
Defined 5 main groups and established evolutionary connections
between all kind of AGB stars and PNe
Stellar evolution and the ‘O-rich AGB sequence’