Abstract

Massive variable stars at low metallicity

Dominik Bomans (Astronomical Institute of the Ruhr-Univ. Bochum)

Kerstin Weis (Astronomical Institute of the Ruhr-University Bochum)

Recently, two transients in very low metallcity (below 1/20 solar) galaxies where detected, which can be interpreted as variable massive stars, likely LBV-like objects. These detections together with the detection of a very luminous long-period star in I Zw 18 opens another window for observational tests of massive star evolution at very low metallicities. Using archival and new broad-and narrow-band imaging as well as spectroscopy of nearby very low metallicity dwarf galaxies we search for other potential LBV-like stars and discuss possible ambiguities in the identification process. Our results will be discussed in context with the nature of LBV-like instabilities and the evolution of massive, low (and very-low) metallicity stars with and without rotation.