EDP Sciences
Free access
Volume 482, Number 1, April IV 2008
Page(s) 255 - 258
Section Stellar atmospheres
DOI http://dx.doi.org/10.1051/0004-6361:20078547
Published online 25 February 2008

A&A 482, 255-258 (2008)
DOI: 10.1051/0004-6361:20078547

Research Note

The most rapidly rotating He-strong emission line star: HR 7355

T. Rivinius1, S. Stefl1, R. H. D. Townsend2, and D. Baade3

1  ESO - European Organisation for Astronomical Research in the Southern Hemisphere, Chile
    e-mail: tiviniu@eso.org
2  Bartol Research Institute, University of Delaware, Newark, DE 19716, USA
3  ESO - European Organisation for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany

(Received 24 August 2007 / Accepted 29 January 2008)

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 $\sigma$ 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.

Key words: stars: emission line, Be -- stars: circumstellar matter -- stars: magnetic fields -- stars: chemically peculiar

© ESO 2008