We probe how common extremely rapid rotation is among massive stars in the early universe by measuring the OBe star fraction in nearby metal-poor dwarf galaxies. We apply a new method that uses broad-band photometry to measure the galaxy-wide OBe star fractions in the Magellanic Clouds and three more distant, more metal-poor dwarf galaxies. We find OBe star fractions of ~20% in the Large Magellanic Cloud (0.5 Z_Solar), and ~30% in the Small Magellanic Cloud (0.2 Z_Solar) as well as in the so-far unexplored metallicity range from 0.1 Z_solar to 0.2 Z_solar occupied by the other three dwarf galaxies. Our results imply that extremely rapid rotation is common among massive stars in metal-poor environments such as the early universe.
@article{arxiv.2210.01453,
title = {Massive stars in metal-poor dwarf galaxies are often extreme rotators},
author = {Abel Schootemeijer and Danny J. Lennon and Miriam Garcia and Norbert Langer and Ben Hastings and Christoph Schürmann},
journal= {arXiv preprint arXiv:2210.01453},
year = {2024}
}
Comments
Conference proceedings for a talk in IAU Symposium 361: Massive Stars Near and Far, Ballyconnell, Ireland, 9-13 May 2022