Rapidly-rotating Population III Stellar Models As A Source Of Primary Nitrogen

By Keith Cowing
Status Report
April 26, 2024
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Rapidly-rotating Population III Stellar Models As A Source Of Primary Nitrogen
The stellar yields of nitrogen (left) and oxygen (right) for Pop III and very low-metallicity (Z = 10−5 ) stars, for different initial rotations and from different authors (Ekström et al. 2012; Limongi & Chieffi 2012; Murphy et al. 2021a, Sibony et al. submitted). The ranges of initial equatorial velocities corresponding to the different coloured curves are indicated. — astro-ph.SR

The first stars might have been fast rotators. This would have important consequences for their radiative, mechanical and chemical feedback.

We discuss the impact of fast initial rotation on the evolution of massive Population III models and on their nitrogen and oxygen stellar yields. We explore the evolution of Population III stars with initial masses in the range of 9Msol < Mini < 120Msol starting with an initial rotation on the Zero Age Main Sequence equal to 70% of the critical one.

We find that with the physics of rotation considered here, our rapidly-rotating Population III stellar models do not follow a homogeneous evolution. They lose very little mass in case mechanical winds are switched on when the surface rotation becomes equal or larger than the critical velocity.

Impact on the ionising flux appears modest when compared to moderately-rotating models. Fast rotation favours, in models with initial masses above ~20Msol, the appearance of a very extended intermediate convective zone around the H-burning shell during the core He-burning phase. This shell has important consequences on the sizes of the He- and CO-cores and thus impacts the final fate of stars. Moreover, it has a strong impact on nucleosynthesis boosting the production of primary 14N.

Fast initial rotation impacts significantly the chemical feedback of Population III stars. Observations of extremely metal-poor stars and/or starbursting regions are essential to provide constraints on the properties of the first stars.

Sophie Tsiatsiou, Yves Sibony, Devesh Nandal, Luca Sciarini, Yutaka Hirai, Sylvia Ekstrom, Eoin Farrell, Laura Murphy, Arthur Choplin, Raphael Hirschi, Cristina Chiappini, Boyuan Liu, Volker Bromm, Jose Groh, Georges Meynet

Comments: Accepted in A&A. Pages 17. Figures 14. Tables 2
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2404.16512 [astro-ph.SR] (or arXiv:2404.16512v1 [astro-ph.SR] for this version)
Submission history
From: Sophie Tsiatsiou
[v1] Thu, 25 Apr 2024 11:14:07 UTC (2,757 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻