Wolf-Rayet stars and O-star runaways with HIPPARCOS. II. Photometry

Abundant {HIPPARCOS photometry over 3 years of 141 O and Wolf-Rayet stars, including 8 massive X-ray binaries, provides a magnificent variety of light curves at the sigma ~ 1-5% level. Among the most interesting results, we mention: optical outbursts in HD 102567 (MXRB), coinciding with periastron passages; drastic changes in the light curve shape of HD 153919 (MXRB); previously unknown long-term variability of HD 39680 (O6V:[n]pe var) and WR 46 (WN3p); unusual flaring of HDE 308399 (O9V); ellipsoidal variations of HD 64315, HD 115071 and HD 160641; rotationally modulated variations in HD 66811=zeta Pup (O4Inf) and HD 210839=lambda Cep (O6I(n)fp); dust formation episode in WR 121 (WC9). In a statistical sense, the incidence of variability is slightly higher among the WR stars, which might be explained by the higher percentage of known binary systems. Among the presumably single WR stars, the candidate runaways appear to be more variable then the rest. Based on data from the ESA Hipparcos astrometry satellite