HD 152248: Evidence for a colliding wind interaction ^*

Institut d'Astrophysique et de Géophysique, Université de Liège, 5 avenue de Cointe, 4000 Liège, Belgium

Corresponding author: H. Sana, sana@astro.ulg.ac.be

Received: 18 December 2000
Accepted: 7 February 2001

Abstract

We present the results of a four year spectroscopic campaign on the early-type binary system HD 152248. Our analysis yields a new classification as O7.5III(f) + O7III(f), in contradiction with previous classifications of the components as supergiants. We derive improved orbital elements and the corresponding masses ( and ) are somewhat larger than previously reported in the literature, although they are still significantly lower than the ones expected from evolutionary tracks. Both components of the system are close to filling their Roche lobe at periastron passage. We also investigate the equivalent width variations of the lines of the two components and we discuss their relation to the Struve-Sahade effect. Finally, we show that the line profile variability of the Heiił4686 and H αlines is consistent with a strong wind interaction between the two stars, quite as predicted by current colliding wind models.