Line profile variability and magnetic fields ofWolf-Rayet stars: WR135 andWR136

摘要

We have obtained spectropolarimetric observations of two Wolf-Rayet stars, WR135 (WC8) and WR136 (WN6), with the 6-m Russian telescope in July 2009 and July 2010. We have studied the He II 5412 A° line region, which contains also the C IV 5469 A° line (for WR135 only). Our goals were to investigate the rapid line-profile variability (LPV) in WR star spectra and to search for magnetic fields. We find small amplitude emission peaks moving from the center of He II line to its wings during the night in spectra of both stars. These emission peaks are likely a signature of accelerating clumps in the stellar wind. We obtained upper limits of the magnetic field strength: ≈200G for WR135 and ≈50G for WR136.