Massive binaries and the enrichment of the interstellar medium in globular clusters

TL;DR

This paper explores the role of massive binary star systems as a significant source of processed material that can explain the chemical abundance anomalies observed in globular cluster stars, proposing an alternative to traditional sources.

Contribution

It introduces massive binaries as a novel and potentially dominant source of processed material for globular cluster star pollution, emphasizing low-velocity ejected matter.

Findings

Massive binaries can eject more processed material than previous sources.

Ejected material from binaries remains within globular clusters, enabling star pollution.

Binary interactions produce low-velocity outflows suitable for star formation or pollution.

Abstract

Abundance anomalies observed in globular cluster stars indicate pollution with material processed by hydrogen burning. Two main sources have been suggested: asymptotic giant branch stars and massive stars rotating near the break-up limit. We discuss the potential of massive binaries as an interesting alternative source of processed material. We discuss observational evidence for mass shedding from interacting binaries. In contrast to the fast, radiatively driven winds of massive stars, this material is typically ejected with low velocity. We expect that it remains inside the potential well of a globular cluster and becomes available for the formation or pollution of a second generation of stars. We estimate that the amount of processed low-velocity material that can be ejected by massive binaries is larger than the contribution of two previously suggested sources combined.