Wack2134 (= WR21a): A New Wolf-Rayet Binary

NIEMELA, V. S.; GAMEN, R. C.; SOLIVELLA, G.; BENAGLIA, P.; REIG, P.; COE, M.J.

Pucon, Chile

Congreso; XI IAU Regional Latin American Meeting of Astronomy; 2005

IAU

We present a radial velocity study of the star Wack134, which shows Wolf-Rayet type emission lines in its optical spectrum. This star, catalogued as WR1a, is a well kown X-ray source. Our spectra show radial velocity variations of large amplitude, from which we have determined an orbital period of 31.6 days. In this period, the radial velocities of WR1a describe a rather eccentric orbit. The value of the mass function determined from our orbital solution is high, over 8 solar masses, indicating that WR1a is a system of two massive stars. The X-ray source therefore could arise in the collision of the stellar winds of the binary components.