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arXiv · 2412.14107

The IACOB project XIII. Helium enrichment in O-type stars as a tracer of past binary interaction

C. Martínez-Sebastián·S. Simón-Díaz·H. Jin·Z. Keszthelyi·G. Holgado·N. Langer·J. Puls
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Abstract

There is increasing evidence that single-star evolutionary models are inadequate to reproduce all observational properties of massive stars. Binary interaction has emerged as a key factor in the evolution of a significant fraction of massive stars. In this study, we investigate the helium ($Y_{\mathrm He}$) and nitrogen ($\epsilon_{\mathrm N}$) surface abundances in a comprehensive sample of 180 Galactic O-type stars with projected rotational velocities $v\sin(i)\leq150{\mathrm km}\cdot{\mathrm s}^{-1}$. We found a subsample ($\sim20\%$ of the total, and $\sim80\%$ of the stars with $Y_{\mathrm He}\geq0.12$) with a $Y_{\mathrm He}$ and $\epsilon_{\mathrm N}$ combined pattern unexplainable by single-star evolution. We argue that the stars with anomalous surface abundance patterns are binary interaction products.

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C. Martínez-Sebastián, S. Simón-Díaz, H. Jin, Z. Keszthelyi, G. Holgado, N. Langer, J. Puls. 2024-12-18. The IACOB project XIII. Helium enrichment in O-type stars as a tracer of past binary interaction. https://doi.org/10.1051/0004-6361%2F202452622

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