Stars: evolution; Stars: massive; Stars: Population II; Stars: rotation; Evolution modeling; Initial composition; Metallicities; Population synthesis; Star: evolution; Stars: Rotation; Stellar evolutions; Stellar modeling; Astronomy and Astrophysics; Space and Planetary Science
Abstract :
[en] Context. Grids of stellar evolution models with rotation using the Geneva stellar evolution code (GENEC) have been published for a wide range of metallicities. Aims. We introduce the last remaining grid of GENEC models, with a metallicity of Z=10-5. We study the impact of this extremely metal-poor initial composition on various aspects of stellar evolution, and compare it to the results from previous grids at other metallicities. We provide electronic tables that can be used to interpolate between stellar evolution tracks and for population synthesis. Methods. Using the same physics as in the previous papers of this series, we computed a grid of stellar evolution models with GENEC spanning masses between 1.7 and 500 M⊙, with and without rotation, at a metallicity of Z=10-5. Results. Due to the extremely low metallicity of the models, mass-loss processes are negligible for all except the most massive stars. For most properties (such as evolutionary tracks in the Hertzsprung-Russell diagram, lifetimes, and final fates), the present models fit neatly between those previously computed at surrounding metallicities. However, specific to this metallicity is the very large production of primary nitrogen in moderately rotating stars, which is linked to the interplay between the hydrogen- and helium-burning regions. Conclusions. The stars in the present grid are interesting candidates as sources of nitrogen-enrichment in the early Universe. Indeed, they may have formed very early on from material previously enriched by the massive short-lived Population III stars, and as such constitute a very important piece in the puzzle that is the history of the Universe.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Sibony, Yves ; Observatoire de Genève, Versoix, Switzerland
Shepherd, Kendall G. ; SISSA, Trieste, Italy
Yusof, Norhasliza ; Department of Physics, Faculty of Science, Universiti Malaya, Kuala Lumpur, Malaysia
Hirschi, Raphael; Astrophysics Group, Keele University, Keele, United Kingdom ; Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo, Kashiwa, Japan
Chambers, Caitlan; Astrophysics Group, Keele University, Keele, United Kingdom
Tsiatsiou, Sophie ; Observatoire de Genève, Versoix, Switzerland
Nandal, Devesh ; Observatoire de Genève, Versoix, Switzerland
Sciarini, Luca ; Observatoire de Genève, Versoix, Switzerland
Moyano, Facundo D. ; Observatoire de Genève, Versoix, Switzerland
Bétrisey, Jérôme ; Observatoire de Genève, Versoix, Switzerland
Buldgen, Gaël ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie ; Observatoire de Genève, Versoix, Switzerland
Georgy, Cyril ; Observatoire de Genève, Versoix, Switzerland
Ekström, Sylvia ; Observatoire de Genève, Versoix, Switzerland
Eggenberger, Patrick; Observatoire de Genève, Versoix, Switzerland
Meynet, Georges; Observatoire de Genève, Versoix, Switzerland
ERC - European Research Council STFC - Science and Technology Facilities Council NSF - National Science Foundation
Funding text :
YS, ST, DN, FDM, CG, SE, PE, and GM have received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 833925, project STAREX). KGS acknowledges funding support by the Italian Ministerial Grant PRIN 2022, \"Radiative opacities for astrophysical applications\", No. 2022NEXMP8, CUP G53D23000910006. NY acknowledges the Fundamental Research Grant Scheme grant number FRGS/1/2018/STG02/UM/01/2 and FRGS/1/2021/STG07/UM/02/4 under Ministry of Higher Education, Malaysia. RH acknowledges support from STFC, the World Premier International Research Centre Initiative (WPI Initiative), MEXT, Japan, the IReNA AccelNet Network of Networks (National Science Foundation, Grant No. OISE-1927130) and the European Union's Horizon 2020 research and innovation programme (ChETECINFRA, Grant No. 101008324). LS has received support from the SNF project No 212143. JB and GB acknowledge funding by the SNF AMBIZIONE grant No 185805 (Seismic inversions and modelling of transport processes in stars).