Spectral variability of the massive X-ray binary LSI +65o010
Received 1 December 1998 / Accepted 7 June 1999
We present optical spectroscopic observations of the massive X-ray binary LSI +65o010, the optical counterpart to the X-ray transient 2S0114+65. Our data show a dramatic variability in 1992 and only a mild variability during 1993-1995. An increase by a factor more than three in the equivalent width of the H emission line within four days is present in Nov. 1992. It is interesting to notice that changes have taken place only in the blue side on Nov. 4, 1992, when compared to similar spectrum taken one day before. We associate this phenomenon with the existence of an HII region around the neutron star. A double-peak profile is seen in the spectrum of Sept. 1994. If this double-peak profile is real, we suggest that such a profile may be explained by the emission line from an HII region around the neutron star, superposed on that from the stellar wind of the supergiant.
Key words: line: profiles stars: individual: LSI +65O 010 stars: supergiants X-rays: stars
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© European Southern Observatory (ESO) 1999
Online publication: October 14, 1999