The Unusual Wolf-Rayet Star EZ CMa

EZ CMa is one of the most unusual WolfRayet stars known. It shows welldefinedvariability in the optical/UV at a period of 3.77 days. The cause of the variability is not known, and it may be due either to binarity or corotatingstructures in the wind of a single star. We propose to obtain a hign S/N EPIC spectrum of EZ CMa, enabling us to search for the hotter plasma which should be present if it is a binary system and to constrain the nature of the companion. Previous ASCA observations suggest that such hotter plasma is present. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]