Yields from massive stars in binaries. Chemical evolution of the Milky Way disk

Abstract

A large fraction of massive stars in the Galaxy reside in binary systems and their evolution is different from that of single stars. The yields of massive stars, which are the main responsible for the production of metals, can be therefore affected by the binary nature of the systems. Recently, Farmer et al. (2023) computed new grids of yields for single and binary-stripped massive stars with solar chemical composition. The main purpose of this paper is to test these yields on the chemical evolution of Galactic stars. To do that, we adopt well-tested chemical evolution models for the Milky Way disk, implementing both yields for single and binary-stripped massive stars. In particular, we assume different percentages of massive binary systems within the initial mass function. We compute the evolution of 22 chemical species starting from $^{4}$He to $^{64}$Zn. Our main results can be summarized as follows: i) when adopting the yields of Farmer et al. (2023), large differences are found relative to the predicted solar abundances by chemical evolution models adopting "standard" massive star yields from the literature for $^{12}$C, $^{14}$N, $^{24}$Mg, $^{39}$K, $^{40}$Ca, $^{55}$Mn and $^{59}$Co. Generally, the yields for single stars reproduce slightly better the observed solar abundances, although for several elements a large fraction of binaries helps in reproducing the observations; ii) different fractions of massive binaries (from 50% to 100%) produce negligible differences in the predicted solar abundances, whereas the differences are more marked between models with and without binary-stripped stellar yields; iii) for the [X/Fe] vs. [Fe/H] relations, the yields including massive stars in binaries produce the best results for $^{52}$Cr, while for $^{12}$C, $^{39}$K, $^{40}$Ca and $^{24}$Mg the best results are obtained with Farmer's yields with no binaries.