Sébastien Martinet

PhD student

Geneva Observatory, 311
+41 22 379 24 55
E-mail

Supervisors: Prof. Georges Meynet and Dr. Sylvia Ekström.

Phyics of Very Massive Stars along the Cosmic History

I'm working on massive stellar evolution with the Geneva stellar evolution code GENEC, and I'm mainly focusing on the very massive stars, especially at very low and zero metallicity, where they might have been abundant. Apart from being spectacular objects, very massive stars (VMS) are also suspected to have a tremendous impact on their environment and, all in all, the whole cosmic evolution. The nucleosynthesis both during their advanced stages and their final explosion likely contribute greatly to the overall enrichment of the Universe. Their extreme conditions lead also to very important radiative and mechanical feedback effects, from local to cosmic scale.

Recent papers: Martinet et al. 2021 (2021A&A...648A.126M)

Martinet et al. 2022

Members

Convective core sizes in rotating massive stars. I. Constraints from solar metallicity OB field stars

Combining stellar evolution models and spectroscopic parameters derived for a large sample of Galactic O and B stars with the inclusion of brand-new information about their projected rotational velocities, we reexamine the question of the convective core size in MS massive stars.

Ionizing photon production of Population III stars: effects of rotation, convection, and initial mass function

This work presents ionizing photon production predictions for the most up to date Geneva stellar evolution models of Population III stars, and provides insight into how key evolutionary parameters impact the contribution of the first stars to reionization.

A new 12C + 12C nuclear reaction rate: impact on stellar evolution

This work presents new 12C + 12C reaction rates in the form of numerical tables with associated uncertainty estimation, as well as analytical formulae that can be directly implemented into stellar evolution codes. This article further describes the impact of these new rates on C-burning in stars.

Grids of stellar models with rotation - V. Models from 1.7 to 120 M⊙ at zero metallicity

Here we compute a grid of stellar evolution models using the Geneva code with the aim to improve our understanding of the evolution of zero-metallicity stars, with particular interest in how rotation affects surface properties, interior structure, and metal enrichment. We produce a range of models of initial masses (Mini) from 1.7 to 120M⊙ , focusing on massive models of 9≤Mini≤120M⊙ .

Grids of stellar models with rotation. VI. Models from 0.8 to 120 M⊙ at a metallicity Z = 0.006

The present models are of particular interest for comparisons with observations in the LMC and also in the outer regions of the Milky Way. We provide public access to numerical tables that can be used for computing interpolated tracks and for population synthesis studies.