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We present the results of an intensive campaign of spectroscopic andphotometric monitoring of the peculiar Wolf-Rayet star WR 134 from 1989 to1997.  This unprecedentedly large data set allows us to confirm unambiguously theexistence of a coherent 2.25 +/- 0.05 day periodicity in the line-profilechanges of He II 4686, although the global pattern of variability is differentfrom one epoch to another. This period is only marginally detected in thephotometric data set. Assuming the 2.25 day periodic variability to be inducedby orbital motion of a collapsed companion, we develop a simple model aiming atinvestigating (i) the effect of this strongly ionizing, accreting companion onthe Wolf-Rayet wind structure, and (ii) the expected emergent X-ray luminosity.We argue that the predicted and observed X-ray fluxes can only be matched ifthe accretion on the collapsed star is significantly inhibited. Additionally,we performed simulations of line-profile variations caused by the orbitalrevolution of a localized, strongly ionized wind cavity surrounding the X-raysource. A reasonable fit is achieved between the observed and modeledphase-dependent line profiles of He II 4686. However, the derived size of thephotoionized zone substantially exceeds our expectations, given the observedlow-level X-ray flux. Alternatively, we explore rotational modulation of apersistent, largely anisotropic outflow as the origin of the observed cyclicalvariability. Although qualitative, this hypothesis leads to greater consistencywith the observations.Comment: 34 pages, 16 figures. Accepted by the Astrophysical Journa

A 2.3 Day Periodic Variability in the Apparently Single Wolf‐Rayet Star WR 134: Collapsed Companion or Rotational Modulation?