Supermassive stars as the origin of the multiple populations in globular clusters

Abstract

Globular clusters (GCs) display anomalous light element abundances (HeCNONaMgAl), resembling the yields of hot-hydrogen burning, but there is no consensus yet on the origin of these ubiquitous multiple populations. We present a model in which a super-massive star (SMS, >10^3 Msun) forms via stellar collisions during GC formation and pollutes the intra-cluster medium. The growth of the SMS finds a balance with the wind mass loss rate, such that the SMS can produce a significant fraction of the total GC mass in processed material, thereby overcoming the so-called mass-budget problem that plagues other models. Because of continuous rejuvenation, the SMS acts as a `conveyer-belt' of hot-hydrogen burning yields with (relatively) low He abundances, in agreement with empirical constraints. Additionally, the amount of processed material per unit of GC mass correlates with GC mass, addressing the specific mass budget problem. We discuss uncertainties and tests of this new self-enrichment scenario.

arXiv comment4 pages, to appear in proceedings of IAUS351 "Star Clusters: from the Milky Way to the Early Universe"

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Cited by in corpus (3)

• Effect of mass loss due to stellar winds on the formation of supermassive black hole seeds in dense nuclear star clusters
• CAPOS: The bulge Cluster APOGEE Survey VI. Characterizing multiple stellar populations and chemical abundances in the bulge globular cluster NGC 6569
• Could kilomasers pinpoint supermassive stars?