Grids of stellar models with rotation VII: models from 0.8 to 300 M-circle dot at supersolar metallicity (Z=0.020)

Yusof, Norhasliza; Hirschi, Raphael; Eggenberger, Patrick; Ekström, Sylvia; Georgy, Cyril; Sibony, Yves; Crowther, Paul A; Meynet, Georges; Abu Kassim, Hasan; Aishah Wan Harun, Wan; Maeder, André; Groh, Jose H; Farrell, Eoin; Murphy, Laura

Abstract

We present a grid of stellar models at supersolar metallicity (Z = 0.020) extending the previous grids of Geneva models at solar and sub-solar metallicities. A metallicity of Z = 0.020 was chosen to match that of the inner Galactic disc. A modest increase of 43 per?cent (= 0.02/0.014) in metallicity compared to solar models means that the models evolve similarly to solar models but with slightly larger mass-loss. Mass-loss limits the final total masses of the supersolar models to 35?M? even for stars with initial masses much larger than 100?M?. Mass-loss is strong enough in stars above 20?M? for rotating stars (25?M? for non-rotating stars) to remove the entire hydrogen-rich envelope. Our models thus predict SNII below 20?M? for rotating stars (25?M? for non-rotating stars) and SNIb (possibly SNIc) above that. We computed both isochrones and synthetic clusters to compare our supersolar models to the Westerlund 1 (Wd1) massive young cluster. A synthetic cluster combining rotating and non-rotating models with an age spread between log10(age/yr) = 6.7 and 7.0 is able to reproduce qualitatively the observed populations of WR, RSG, and YSG stars in Wd1, in particular their simultaneous presence at log10(L/L?) = 5–5.5. The quantitative agreement is imperfect and we discuss the likely causes: synthetic cluster parameters, binary interactions, mass-loss and their related uncertainties. In particular, mass-loss in the cool part of the HRD plays a key role.

Citation

Yusof, N., Hirschi, R., Eggenberger, P., Ekström, S., Georgy, C., Sibony, Y., Crowther, P. A., Meynet, G., Abu Kassim, H., Aishah Wan Harun, W., Maeder, A., Groh, J. H., Farrell, E., & Murphy, L. (2022). Grids of stellar models with rotation VII: models from 0.8 to 300 M-circle dot at supersolar metallicity (Z=0.020). Monthly Notices of the Royal Astronomical Society, 511(2), 2814 - 2828. https://doi.org/10.1093/mnras/stac230

• Journal Article Type: Article
• Acceptance Date: Jan 20, 2022
• Online Publication Date: Jan 31, 2022
• Publication Date: Feb 15, 2022
• Publicly Available Date: May 30, 2023
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 511
• Issue: 2
• Pages: 2814 - 2828
• DOI: https://doi.org/10.1093/mnras/stac230
• Keywords: stars: evolution; massive; rotation
• Public URL: https://keele-repository.worktribe.com/output/422820
• Publisher URL: https://academic.oup.com/mnras/article-abstract/511/2/2814/6517701?redirectedFrom=fulltext