2013A&A...552A.131V


C.D.S. - SIMBAD4 rel 1.7 - 2020.02.17CET11:14:18

2013A&A...552A.131V - Astronomy and Astrophysics, volume 552A, 131-131 (2013/4-1)

Population II stars and the Spite plateau. Stellar evolution models with mass loss.

VICK M., MICHAUD G., RICHER J. and RICHARD O.

Abstract (from CDS):

We aim to determine the constraints that observed chemical abundances put on the potential role of mass loss in metal poor dwarfs. Self-consistent stellar evolutionary models that include all the effects of atomic diffusion and radiative accelerations for 28 chemical species were computed for stellar masses between 0.6 and 0.8M. Models with an initial metallicity of Z0=0.00017 and mass loss rates from 10–15M/yr to 10–12M/yr were calculated. They were then compared to previous models with mass loss, as well as to models with turbulent mixing. For models with an initial metallicity of [Fe/H]0=-2.31, mass loss rates of about 10–12M/yr lead to surface abundance profiles that are very similar to those obtained in models with turbulence. Both models have about the same level of agreement with observations of galactic-halo lithium abundances, as well as lithium and other elemental abundances from metal poor globular clusters such as NGC6397. In this cluster, models with mass loss agree slightly better with subgiant observations of Li abundance than those with turbulence. Lower red giant branch stars instead favor the models with turbulence. Larger differences between models with mass loss and those with turbulence appear in the interior concentrations of metals. The relatively high mass loss rates required to reproduce plateau-like lithium abundances appear unlikely when compared to the solar mass-loss rate. However the presence of a chromosphere on these stars justifies further investigation of the mass-loss rates.

Abstract Copyright:

Journal keyword(s): diffusion - stars: abundances - stars: interiors - stars: Population II - stars: mass-loss

Simbad objects: 3

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Number of rows : 3

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 * alf CMa SB* 06 45 08.91728 -16 42 58.0171 -1.51 -1.46 -1.46 -1.46 -1.43 A1V+DA 1383 0
2 M 92 GlC 17 17 07.39 +43 08 09.4     6.52     ~ 1887 0
3 NGC 6397 GlC 17 40 42.09 -53 40 27.6   7.39 5.17     ~ 1775 1

    Equat.    Gal    SGal    Ecl

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2020.02.17-11:14:18

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