August 7-10, 2017

Abstract

Wolf-Rayet stars with BRITE

Anthony Moffat (Univ. de Montreal)

and the Massive-star Team

Wolf-Rayet stars hide their hot stellar surface by a fast thick wind. They come in three varieties: (a) He-burning remnants of massive stars with Mi .GT. c. 20 Mo, (b) H-burning stars of the upper MS with Mi .GT. c. 60 Mo and (c) c. 15% of CSPNe. BRITE`s ability to obtain long, high-precision, high-cadence photometric runs in two bands is potentially of great value to probe variable structures in their winds, which are fundamental in their understanding, and detect pulsations from the underlying star if they are not filtered out by the wind, as well as to constrain WR properties in binaries. So far BRITE has observed four WR stars: (1) gamma-2 Vel, the brightest WR in the sky, in a 78d binary (Richardson et al., submitted), (2) EZ CMa, a single WR star with clear co-rotating interaction regions (CIR) in its wind, and the faintest star observed so far by BRITE (St-Louis et al., in prep.), (3) theta Mus, the second-brightest WR in the sky, a triple containing a 19d binary (Pablo et al., in prep.), and (4) WR24, a massive single star of class (b) in the Carina Nebula and the only WR star that showed P-Cygni type absorption features associated with CIRs in its wind with the IUE satellite (St-Louis et al., in prep.). The first three stars belong to class (a). We report here on the exciting results of stars (1) and (2), for which we also have simultaneous, high-quality, ground-based spectroscopy.

Mode of presentation need to be confirmed by the SOC