Spectral and photometric studies of the Wolf-Rayet star WR 134 = HD 191765

Abstract

The results of spectral and photometric observations of the Wolf-Rayet star WR 134 = HD 191765 performed at the N. Tusi Shamakha Astrophysical Observatory (ShAO) of the National Academy of Sciences of Azerbaijan in 2006–2010 are presented. The spectral observations were carried out at the ShAO Zeiss-2000 telescope with an echelle spectrometer. Thirty-four echelle spectrograms of WR 134 were obtained. Profiles of the five strongest emission lines were analyzed: HeII 4859, HeII 5411, CIV 5808, HeI 5875, and (HeII+Hα) 6560. Various parameters of these emission lines are determined: their equivalent widths, radial velocities, central intensities, and half-widths. Only the radial velocity was found to be variable. Variability of the shapes of all emission-line profiles was found, but the largest changes are observed for the (HeII+Hα) 6560 emission band. Photometric observations were carried out at the ShAO Zeiss-600 telescope using an Alta U-47 CCD array (1024 × 1024 pixels) in the V filter of the photometric UBV system. Photometric observations were carried out on 18 nights, with from 100 to 300 measurements made during each night. The mean V magnitudes of WR 134 and a control star were determined for each night. Variability of WR 134 was detected, both within a night and during the entire observation period. The exposure time varied from 1 to 6 s on different nights. A statistical analysis of the mean magnitudes indicated that this series contains a peak at a frequency of ν = 0.530 day⁻¹, corresponding to the period P = 1.887^d. This period is interpreted as the manifestation binarity for this star. It is suggested that the secondary component of the system may be a low-mass optical K-M star.