LOW-METALLICITY MASSIVE SINGLE STARS WITH ROTATION

Abstract

Massive low-metallicity stars are essential for understanding cosmic history. These stars are thought to be the progenitors of certain types of supernovae, gamma-ray bursts, and gravitational wave-emitting mergers. These exotic phenomena contribute to their host galaxies through intense ionising radiation and energy and momentum feedback. To better understand the nature of
these stars and to quantify the feedback from them to their host galaxies, spectroscopic observations of these stars and their analyses are of great importance. We focus on a certain type of very metal-poor (0.02 Z⊙) hot massive single stars that rotate fast and evolve chemically homogeneously. Combining state-of-the-art theories of stellar evolution and stellar atmosphere
modelling, we predict synthetic spectra and wind properties of these stars corresponding to different masses and evolutionary phases. The Hubble Space Telescope’s Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) project will allow us to compare our predicted spectra with observations of stars of similar nature (e.g. metal-poor stars in Sextant A).