Very peculiar wind from BD+53°2790, the optical counterpart to 4U 2206+54

Blay, P.; Ribó, M.; Negueruela, I.
Bibliographical reference

Astrophysics and Space Science, Volume 320, Issue 1-3, pp. 145-148

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4
2009
Number of authors
3
IAC number of authors
0
Citations
6
Refereed citations
5
Description
BD+53°2790, an O9.5V star, is the optical counterpart to the HMXRB 4U 2206+54. This system was classified initially as a BeX, but observational evidence soon stressed the need to revise this classification. The permanent asymmetry in the H α line profiles (in contrast with the cyclic variations shown by Be stars), the variations in the profile of this line in time scales of hours (while time scales from weeks to months are expected in Be stars), and the lack of correlation between IR observables and H α line parameters, strongly suggest that, while BD+53°2790 contains a circumstellar disc, it is not like the one present in Be stars (Blay et al. 2006). Furthermore, there is evidence of overabundance of He in BD+53°2790. Together with the presence of an anomalous wind, found through UV spectroscopy, the possibility to link this star with the group of He rich stars is open. We will discuss the work done with IUE data from BD+53°2790 and the unexpected finding of a slow and dense wind, very rare for an O9.5V star.
Type