He-enriched STAREVOL models for globular cluster multiple populations: Self-consistent isochrones from ZAMS to the TP-AGB phase

被引:0
|
作者
Costa, G. [1 ]
Dumont, T. [2 ]
Lancon, A. [3 ]
Palacios, A. [4 ]
Charbonnel, C. [5 ,6 ,7 ]
Prugniel, P. [1 ]
Ekstrom, S. [5 ]
Georgy, C. [5 ]
Branco, V. [3 ,8 ]
Coelho, P. [8 ]
Martins, L. [9 ]
Borisov, S. [5 ]
Voggel, K. [3 ]
Chantereau, W. [3 ]
机构
[1] Univ Lyon1, Univ Lyon, CNRS, Ctr Rech Astrophys Lyon,UMR 5574,ENS Lyon, F-69230 St Genis Laval, France
[2] Univ Strasbourg, CNRS, IPHC, UMR 7178, F-67000 Strasbourg, France
[3] Univ Strasbourg, CNRS, Observ Astronom Strasbourg, UMR 7550, 11 Rue Univ, F-67000 Strasbourg, France
[4] Univ Montpellier, CNRS, LUPM, Pl Eugene Bataillon, F-34095 Montpellier, France
[5] Univ Geneva, Dept Astron, Chemin Pegasi 51, CH-1290 Versoix, Switzerland
[6] CNRS, IRAP, UMR 5277, 14 Ave Edouard Belin, F-31400 Toulouse, France
[7] Univ Toulouse, 14 Ave Edouard Belin, F-31400 Toulouse, France
[8] Univ Sao Paulo, IAG, Rua Matao 1226, BR-05508090 Sao Paulo, SP, Brazil
[9] NAT Univ Cidade Sao Paulo, Rua Galvao Bueno 868, BR-01506000 Sao Paulo, SP, Brazil
基金
巴西圣保罗研究基金会; 瑞士国家科学基金会; 欧洲研究理事会;
关键词
stars: abundances; stars: AGB and post-AGB; stars: evolution; stars: low-mass; globular clusters: general; ASYMPTOTIC GIANT BRANCH; INTERMEDIATE-MASS STARS; UV LEGACY SURVEY; M-CIRCLE-DOT; INITIAL HELIUM ABUNDANCE; PRE-MAIN-SEQUENCE; METAL-POOR STARS; STELLAR POPULATIONS; THEORETICAL ISOCHRONES; SUPERMASSIVE STARS;
D O I
10.1051/0004-6361/202449741
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
A common property of globular clusters (GCs) is to host multiple populations characterized by peculiar chemical abundances. Recent photometric studies suggest that the He content could vary between the populations of a GC by up to Delta He similar to 0.13, in mass fraction. The initial He content impacts the evolution of low-mass stars by ultimately modifying their lifetimes, luminosity, temperatures, and, more generally, the morphology of post-red giant branch (RGB) evolutionary tracks in the Hertzsprung-Russell diagram. We present new physically accurate isochrones with different initial He enrichments and metallicities, with a focus on the methods implemented to deal with the post-RGB phases. The isochrones are based on tracks computed with the stellar evolution code STAREVOL for different metallicities (Z=0.0002, 0.0009, 0.002, and 0.008) and with a different He enrichment (from 0.25 to 0.6 in mass fraction). We describe the effect of He enrichment on the morphology of the isochrones, and we tested these by comparing the predicted number counts of horizontal branch and asymptotic giant branch stars with those of selected GCs. Comparing the number ratios, we find that our new theoretical ones agree with the observed values within 1 sigma in most cases. The work presented here sets the ground for future studies on stellar populations in GCs, in which the abundances of light elements in He-enhanced models will rely on different assumptions for the causes of this enrichment. The developed methodology permits the computation of isochrones from new stellar tracks with noncanonical stellar processes. The checked number counts ensure that, at least in this reference set, the contribution of the luminous late stages of stellar evolution to the integrated light of a GC is represented adequately.
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页数:15
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