The most rapidly rotating He-strong emission line star: HR 7355
Baade, D.;
Rivinius, T.;
Townsend, R. H. D.;
Tefl, S. Å.
Chile, United States, Germany
Abstract
Aims: We searched for massive stars with Balmer emission consistent with magnetically confined circumstellar material.
Methods: Archival spectroscopic and photometric data were investigated.
Results: HR 7355 is a formerly unknown He-strong star showing Balmer emission. At V = 6.02 mag, it is one of the brightest objects simultaneously showing anomalous helium absorption and hydrogen emission. Among similar objects, only σ Ori E has so far been subjected to any systematic analysis of the circumstellar material responsible for the emission. We argue that the double-wave photometric period of 0.52 d corresponds to the rotation period. In tandem with the high projected equatorial velocity, v sin i = 320 km s-1, this short period suggests that HR 7355 is the most rapidly rotating He-strong star known to date; a class that was hitherto expected to host stars with slow to moderate rotation only.
Based on
observations collected at La Silla, ESO-Chile (Prop. 063.H-0080, 073.D-0234).
2008
•
Astronomy and Astrophysics
IUE
19
