EDP Sciences
Free access
Volume 508, Number 2, December III 2009
Page(s) 895 - 900
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361/200912638
Published online 27 October 2009
A&A 508, 895-900 (2009)
DOI: 10.1051/0004-6361/200912638

Optical and X-ray outbursts of Be/X-ray binary system SAX J2103.5+4545

Ü. Kızıloğlu, S. Özbilgen, N. Kızıloğlu, and A. Baykal

Physics Department, Middle East Technical University, Ankara 06531, Turkey
    e-mail: umk@astroa.physics.metu.edu.tr

Received 5 June 2009 / Accepted 13 October 2009

Aims. The main goal of this study is to investigate the relationship between the optical and X-ray behaviours of the Be/X-ray binary system SAX J2103.5+4545 .
Methods. We present the relations between the H$\alpha$ equivalent width, optical brightness and X-ray flux of the system, by analysing the optical photometric and spectroscopic observations together with the X-ray observations .
Results. The X-ray outburst of the system occurred just after the optical outburst. The nearly symmetric H$\alpha$ emission line profiles observed during the beginning of the optical outburst turn into asymmetric profiles with increased EW values during the dissipation of the Be disc. A correlation between the H$\alpha$ emission line strength and the X-ray flux was found. The H$\alpha$ line indicates the existence of an equatorial disc around the Be star. The H$\alpha$ line changed from emission to absorption during the observation period. The observed double peaked HeI emission lines might come from the accretion disc of neutron star which is temporarily formed at the time of X-ray outburst.

Key words: stars: emission-line, Be -- stars: early-type -- stars: variables: general -- X-rays: binaries

© ESO 2009