J/A+A/490/769 Yields from extremely metal-poor stars (Campbell+, 2008)
Evolution and nucleosynthesis of extremely metal poor & metal-free low- and
intermediate-mass stars.
I: Stellar yield tables and the CEMPs.
Campbell S.W., Lattanzio J.C.
<Astron. Astrophys. 490, 769 (2008)>
=2008A&A...490..769C 2008A&A...490..769C
ADC_Keywords: Models, evolutionary ; Stars, halo ; Abundances
Keywords: stars: evolution - stars: interiors - Galaxy: halo -
stars: AGB and post-AGB
Abstract:
The growing body of spectral observations of the extremely metal-poor
(EMP) stars in the Galactic Halo provides constraints on theoretical
studies of the chemical and stellar evolution of the early Universe.
To calculate yields for EMP stars for use in chemical evolution
calculations and to test whether such models can account for some of
the recent abundance observations of EMP stars, in particular the
highly C-rich EMP (CEMP) halo stars.
We modify an existing 1D stellar structure code to include
time-dependent mixing in a diffusion approximation. Using this code
and a post-processing nucleosynthesis code we calculate the structural
evolution and nucleosynthesis of a grid of models covering the
metallicity range: -6.5≤[Fe/H]≤-3.0 (plus Z=0), and mass range:
0.85≤M≤3.0M☉, amounting to 20 stars in total.
Description:
Each of the first 5 tables contains stellar model chemical yields for
4 stars with initial masses: M=0.85, 1.0, 2.0, 3.0M☉ at a
particular metallicity. The metallicities are: Z=0 and [Fe/H]=-6.5,
-5.45, -4.0, -3.0. Note that the [Fe/H]=-4.0, 3M☉ yield is
missing due to a data loss (table4.dat). We also include a table
containing the remnant core masses for each star (table6.dat). The
yields are given in mass fraction integrated over the lifetime of the
star (see paper for details). The models were evolved from the zero
age main sequence up to the end of the asymptotic giant branch (AGB)
phase. Time dependent mixing was calculated using a diffusion
approximation. Opacities were updated to Iglesias & Rogers
(1996ApJ...464..943I 1996ApJ...464..943I) (for mid-range temperatures) and Ferguson et al.
(2005ApJ...623..585F 2005ApJ...623..585F) (for low temperatures). The Reimers
(1975MSRSL...8..369R 1975MSRSL...8..369R) mass loss formula was used during the RGB phase
and the Vassiliadis & Wood (1993ApJ...413..641V 1993ApJ...413..641V) formula during the
AGB phase. No overshoot was applied.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 87 39 *Yields for Z=0.0
table2.dat 87 39 *Yields for [Fe/H]=-6.5
table3.dat 87 39 *Yields for [Fe/H]=-5.45
table4.dat 71 39 *Yields for [Fe/H]=-4.0
table5.dat 87 39 *Yields for [Fe/H]=-3.0
table6.dat 33 5 Remnant core masses for all models
--------------------------------------------------------------------------------
Note on table1.dat, table2.dat, table3.dat, table4.dat, table5.dat:
M=(0.85, 1.0, 2.0, 3.0)M☉
--------------------------------------------------------------------------------
See also:
VI/109 : Pop. Synth. Models at very low metallicities (Schaerer, 2003)
J/A+A/285/473 : Low-mass stars (Forestini 1994)
J/A+A/327/1039 : Structure and evolution of low-mass stars (Chabrier+ 1997)
J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)
J/A+AS/141/371 : Low-mass stars evolutionary tracks+isochrones (Girardi+, 2000)
J/ApJS/155/651 : Evolution of extremely metal-poor stars (Herwig+, 2004)
J/A+A/432/861 : Yields of low and intermediate mass stars (Gavilan+, 2005)
J/A+A/462/107 : Simulations of metal-poor star clusters (Fagiolini+, 2007)
Byte-by-byte Description of file (#): table[12345].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- Elem Chemical species names
7- 8 I2 --- A Nucleon number A
10- 23 E14.7 --- Init Initial abundance for this chemical species
26- 39 E14.7 --- M0.85 Yield from 0.85M☉ model for this species (1)
42- 55 E14.7 --- M1.00 Yield from 1.00M☉ model for this species (1)
58- 71 E14.7 --- M2.00 Yield from 2.00M☉ model for this species (1)
74- 87 E14.7 --- M3.00 ? Yield from 3.00M☉ model for this species (1)
Not calculated in table4
--------------------------------------------------------------------------------
Note (1): In fractional mass unit.
--------------------------------------------------------------------------------
Byte-by-byte Description of file (#): table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 F5.2 [Sun] [Fe/H] Metallicity (Units: [Fe/H] except for Z=0)
7- 12 F6.3 solMass Rem0.85 Remnant mass of 0.85M☉ model at this Z
14- 19 F6.3 solMass Rem1.00 Remnant mass of 1.00M☉ model at this Z
21- 26 F6.3 solMass Rem2.00 Remnant mass of 2.00M☉ model at this Z
28- 33 F6.3 solMass Rem3.00 ? Remnant mass of 3.00M☉ model at this Z
--------------------------------------------------------------------------------
Acknowledgements:
Simon Campbell, simcam(at)asiaa.sinica.edu.tw
(End) Patricia Vannier [CDS] 16-Sep-2008