Aluminium-26 from massive binary stars I: non-rotating models

TL;DR

This study investigates how binary interactions in massive stars influence the production of Aluminium-26, revealing that binary mass transfer can significantly alter yields, with implications for understanding early Solar System radionuclide sources.

Contribution

First to analyze the effect of binary interactions on Aluminium-26 yields in massive stars using MESA models, filling a gap in previous research.

Findings

Binary interactions can increase or decrease Al26 yields depending on initial conditions.

Mass-loss in binary systems contributes less to Al26 compared to supernovae.

Implications for identifying stellar sources of early Solar System Al26.

Abstract

Aluminium-26 is a short-lived radionuclide with a half-life of 0.72Myr, which is observed today in the Galaxy via gamma-ray spectroscopy and is inferred to have been present in the early Solar System via analysis of meteorites. Massive stars are considered the main contributors of Al26. Although most massive stars are found in binary systems, the effect, however, of binary interactions on the Al26 yields have not been investigated since Braun & Langer (1995). Here we aim to fill this gap. We have used the MESA stellar evolution code to compute massive (10Msun<=M<=80Msun), non-rotating, single and binary stars of solar metallicity (Z=0.014). We computed the wind yields for the single stars and for the binary systems where mass transfer plays a major role. Depending on the initial mass of the primary star and orbital period, the Al26 yield can either increase or decrease in a binary system. For binary systems with primary masses up to ~35-40Msun, the yield can increase significantly, especially at the lower mass-end, while above ~45Msun the yield becomes similar to the single star yield or even decreases. Our preliminary results show that compared to supernova explosions, the contribution of mass-loss in binary systems to the total Al26 abundance produced by a stellar population is minor. On the other hand, if massive star mass-loss is the origin of Al26 in the early Solar System, our results will have significant implications for the identification of the potential stellar, or stellar population, source.