Volume 477, Number 2, January II 2008
|Page(s)||593 - 609|
|Section||Stellar structure and evolution|
|Published online||23 October 2007|
Sternberg Astronomical Institute, Moscow University, Universitetskij Prospect 13, Moscow 119992, Russia e-mail: email@example.com
2 Institut d'Astrophysique et de Géophysique, Université de Liège, Allée du 6 août, 17 Bât. B5c, 4000 Liège, Belgium
3 Department of Physics and Astronomy, University of Glasgow, Kelvin Building, Glasgow G12 8QQ, Scotland, UK
4 SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
5 Astronomical Institute Anton Pannekoek, University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands
Accepted: 10 October 2007
Aims.X-ray properties of the stellar population in the Carina OB1 association are examined with special emphasis on early-type stars. Their spectral characteristics provide some clues to understanding the nature of X-ray formation mechanisms in the winds of single and binary early-type stars.
Methods.A timing and spectral analysis of five observations with XMM-Newton is performed using various statistical tests and thermal spectral models.
Results.235 point sources have been detected within the field of view. Several of these sources are probably pre-main sequence stars with characteristic short-term variability. Seven sources are possible background AGNs. Spectral analysis of twenty four sources of type OB and WR 25 was performed. We derived spectral parameters of the sources and their fluxes in three energy bands. Estimating the interstellar absorption for every source and the distance to the nebula, we derived X-ray luminosities of these stars and compared them to their bolometric luminosities. We discuss possible reasons for the fact that, on average, the observed X-ray properties of binary and single early type stars are not very different, and give several possible explanations.
Key words: stars: early-type / stars: binaries: general / X-rays: stars
Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA). The X-ray catalogue and its cross-identification with infra-red and optical catalogues (Tables [see full text] and [see full text]) are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/477/593
© ESO, 2007
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