Discrete absorption components in the massive LBV Binary MWC 314

摘要

We investigate the physical properties of large-scale wind structures aroundmassive hot stars with radiatively-driven winds. We observe Discrete AbsorptionComponents (DACs) in optical He I P Cygni lines of the LBV binary MWC 314(Porb=60.8 d). The DACs are observed during orbital phases when the primary isin front of the secondary star. They appear at wind velocities between -100km/s and -600 km/s in the P Cyg profiles of He I lam5875, lam6678, and lam4471,signaling high-temperature expanding wind regions of enhanced density andvariable outflow velocity. The DACs can result from wave propagation linked tothe orbital motion near the low-velocity wind base. The He I lines indicate DACformation close to the primary's surface in high-temperature wind regions infront of its orbit, or in dynamical wind regions confined between the binarystars. We observed the DACs with Mercator-HERMES on 5 Sep 2009, 5 May 2012, and6 May 2014 when the primary is in front of the secondary star. XMM-Newtonobservations of 6 May 2014 significantly detected MWC 314 in X-rays at anaverage rate of ~0.015 cts/s.