The first orbital solution for the massive colliding wind binary HD93162 (=WR25)

GAMEN, R. C.; GOSSET, E.; MORRELL, N. I.; NIEMELA, V. S.; SANA, H.; NAZÉ, Y.; RAUW, G.; BARBÁ, R.; SOLIVELLA, G.

Cariló, Buenos Aires, Argentina

Workshop; Massive stars: Fundamental parameters and circumstellar materia; 2006

FCAyG, UNLP

Since the discovery, with EINSTEIN, of strong X-ray emission associated with HD~93162, this object was recurrently predicted by some authors to be a colliding-wind binary system. However, radial-velocity variations that would prove the suspected binary nature have never been found so far. We spectroscopically monitored this object in order to investigate its possible variability and to provide ananswer to the above-mentioned discordance. We derived radial velocities from spectroscopic data acquired mainly between 1994 and 2006, and searched for periodicities. For the first time, periodic radial-velocity variations are detected. Our analysis definitively shows that the Wolf-Rayet star WR~25 is actually an eccentric binary system with a probable period of about 208 days.