Ln. Georgiev et al., Long-term coherent variations in the WR system EZ Canis Majoris: the binary scenario revisited, ASTRON ASTR, 347(2), 1999, pp. 583-589
An analysis of seven different spectroscopic and eight photometric sets of
observations of the WN5 star HD 50896=EZ CMa, distributed over more than 15
years is used to refine the known 3.76 days period. The value of P = 3.765
0 +/- 0.0001d yields variations which have coherent phase-dependence. Altho
ugh not conclusive, this coherence in the 3.7650 day periodic variations ov
er such a long time revives scenarios in which HD 50896 consists of a binar
y system, a hypothesis that had been nearly completely discarded over the p
ast few years. A binary scenario is not in contradiction with the presence
of a non-spherically symmetric wind distribution or instabilities in the WR
star's wind and, in fact, mechanisms such as these are probably responsibl
e for the difficulty in having until now obtained a period which yields coh
erent variations. The low X-ray fluxes suggest that the possible companion
may not be a collapsed object, or that the accretion process is inhibited.