Origin of the [Mg/Fe] dependence of binary formation and evolution

Determine how differences in stellar formation history associated with [Mg/Fe] translate into binary formation and evolution on the small spatial scales relevant to close binaries.

Background

The paper finds that the binary fraction has a weaker dependence on [Mg/Fe] than on [Fe/H], with a modest positive relation at relatively high metallicity but no statistically significant trend at lower metallicity. The authors suggest that [Mg/Fe] may trace formation epoch, enrichment history, and correlated birth-environment properties rather than exerting a direct chemical influence on binary formation. They explicitly leave unresolved how these formation-history differences affect binary formation and subsequent evolution at the small scales relevant to close systems.