The wind of variable C in M33

Abstract

We discuss the spectrum of Var C in M33 obtained just before the onset of its current brightening and its recent spectra during its present "eruption" or optically thick wind stage. These spectra illustrate the typical luminous blue variable (LBV) transition in apparent spectral type or temperature that characterizes the classical LBV or S Dor-type variability. LBVs are known to have slow, dense winds during their maximum phase. Interestingly, Var C had a slow wind even during its hot, quiescent stage in comparison with the normal hot supergiants with similar temperatures. Its outflow or wind speeds also show very little change between these two states. © 2014. The American Astronomical Society. All rights reserved.