EDP Sciences
Free access
Volume 475, Number 2, November IV 2007
Page(s) 677 - 684
Section Stellar atmospheres
DOI http://dx.doi.org/10.1051/0004-6361:20077429

A&A 475, 677-684 (2007)
DOI: 10.1051/0004-6361:20077429

X-ray emission from A-type stars

C. Schröder and J. H. M. M. Schmitt

Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
    e-mail: cschroeder@hs.uni-hamburg.de

(Received 7 March 2007 / Accepted 10 September 2007)

Being fully radiative, stars of spectral type A are not expected to harbor magnetic dynamos and hence such stars are not expected to produce X-ray emission. Indeed, while the X-ray detection rate of such stars in X-ray surveys is low, it is not zero and some of the brighter A-type stars have been detected on different occasions and with different instruments. To study systematically the puzzle of the X-ray emitting A-type stars, we carried out an X-ray study of all A-type stars listed in the Bright Star Catalogue using the ROSAT public data archive. We found a total of 312 bright A-type stars positionally associated with ROSAT X-ray sources; we analyzed the X-ray light curves as well as searched for evidence of RV variations to identify possible late-type companions producing the X-ray emission. In this paper we present a list of X-ray active A-type stars, including the collected data about multiplicity, X-ray luminosity and spectral peculiarities.

Key words: X-rays: stars -- stars: activity -- stars: coronae -- stars: general

© ESO 2007

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