Intensive high-precision photometric monitoring of the variable WN6 Wolf-Rayet star HD 191765

Abstract

Nine nearly contiguous nights of intensive V-band photometry of the WN6 star HD 191765 from 1990 August 21 to 31 show mainly irregular, noisy variability on different time scales from a few hours to several days. The dominating detectable nightly time scales range over ∼ 5-10 hr with amplitudes ≤ 0.007 mag. The main source of this variability is likely related to the recently proposed scenario of stochastic blob propagation in the wind, with a time scale of the order of 10 hr. However, there is also evidence for a 2 day quasi-periodicity as seen in some previous data