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Astron. Astrophys. 330, 201-205 (1998)

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Hipparcos results on massive X-ray binaries

Claude Chevalier and Sergio A. Ilovaisky

Observatoire de Haute-Provence (CNRS), F-04870 St.Michel l'Observatoire, France (chevalierobs-hp.fr)

Received 28 August 1997 / Accepted 17 September 1997


We present results on parallaxes, magnitudes and proper motions for 17 optically identified massive X-ray binaries (MXRB) which were observed during the Hipparcos astrometry mission. This sample includes the sources detected in the medium-energy range (2-10 keV) having optical counterparts brighter than V =12. We compare the Hipparcos results with ground-based optical data and derive probable values for absolute magnitudes and peculiar tangential velocities ([FORMULA]). The 4 OB supergiant systems in our sample are high-velocity objects (the average value of [FORMULA] is greater than 60 km/s), while the 13 Be systems have low velocities ([FORMULA] km/s), suggesting a different formation mechanism for the two subgroups. The unusual X-ray/radio source LSI+ [FORMULA] 303 lies much closer than previously believed and its low optical luminosity ([FORMULA]) and blue intrinsic colors now suggest it may be a peculiar type of low-mass X-ray binary.

Key words: stars: distances – stars: kinematics – stars: Be – X-rays: stars

Send offprint requests to: C.Chevalier

© European Southern Observatory (ESO) 1998

Online publication: January 8, 1998