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., …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
• 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
• Publisher URL: https://academic.oup.com/mnras/article-abstract/511/2/2814/6517701?redirectedFrom=fulltext