J/A+AS/119/37 J/A+AS/119/37 EZ CMa UBV & VBLUW photometry M F J Duijsens K A van der Hucht A M van Genderen H E Schwarz H P J Linders O M Kolkman Astron. Astrophys. Suppl. Ser. 119 37 1996 1996A&AS..119...37D Photometry, UBV Photometry, Vilnius Stars, Wolf-Rayet binaries: close stars: individual (WR 6, HD 50896, EZ Cma) stars: variables: general stars: Wolf-Rayet We present and analyse photometric and spectroscopic observations of the WN5 star EZ Canis Majoris obtained over a period of 7 years. We discuss the changing light curve, the shift in phase of the maxima and point to flare type variability seen in one night. Small amplitude variations are reported in another night. We have investigated the change of the average visual magnitude over a time span of 18 years and found a tentative cyclic variation with a time scale of 2425d (6.6yr) with a range of ~0.07mag. This, of course, should be verified. If true, a precession phenomenon may offer an explanation. The trend of the maximum light amplitude of the 3.766d cycle is also investigated and it shows a saw-tooth character with a timescale of ~400d. A possible relation with the magnetic activity of the star is discussed. We conclude that the line emission variability can be caused by both a single star model with an ever-changing wind and a binary (WN+NS) model.

EZ CMaWR 6HD 5089606 54 12.97-23 55 42.0

HJD Heliocentric julian date d DVmag Relative V Johnson magnitude mag DB-V Relative Johnson B-V color mag DU-B Relative Johnson U-B color mag HJD Heliocentric julian date d DVmag Relative V magnitude (log intensity) mag DBmag Relative B magnitude (log intensity) mag DLmag Relative L magnitude (log intensity) mag DUmag Relative U magnitude (log intensity) mag DWmag Relative W magnitude (log intensity) mag Patricia Bauer CDS 1996Feb14M.F.J. Duijsens <duijsens@strw.LeidenUniv.nl> J_A+AS_119_37.xml