Abstract

Contributed Talk - Splinter MassiveStars

Monday, 09 September 2024, 17:35   (S23)

Population of OB-type stars in the Magellanic Bridge

Elisa Schösser, Varsha Ramachandran, Andreas Sander
ZAH/ARI, Universität Heidelberg

Studying massive stars in low-metallicity environments is crucial for understanding their impact on galaxy formation and chemical enrichment during the early, high-redshift Universe. However, observations of stars in environments with metallicities lower than that of the Small Magellanic Cloud (SMC,Z_SMC ~ 0.2 Z_sol) are scarce. Until recently, massive stars with metallicities below those of the SMC were only known in compact dwarf galaxies, with observations in such distant locations suffering from limited signal-to-noise ratios and spatial resolution. Recently, we discovered three O stars and several early B-type stars in the Magellanic Bridge - a stream of gas and stars linking the two Magellanic Clouds. By combining newly acquired HST UV spectra with archival optical data, we measure the intrinsic iron abundances of these stars for the first time and characterise their wind properties. Our method involves using detailed expanding non-LTE atmosphere models to generate synthetic spectra, which we compare to the optical and UV observations. This led to the discovery of the first nearby massive O star with a metallicity significantly lower than that of the SMC, reaching as low as 0.06 Z_sol.