HD 152248: Evidence for a colliding wind interaction

We present the results of a four year spectroscopic campaign on the early-t ype binary system HD 152248. Our analysis yields a new classification as 07 .5III(f) + 07III(f), in contradiction with previous classifications of the components as supergiants. We derive improved orbital elements and the corr esponding masses (M-1 = 29.61M(circle dot) and M-2= 29.9 M-circle dot) are somewhat larger than previously reported in the literature, although they a re still significantly lower than the ones expected from evolutionary track s. Both components of the system are close to filling their Roche lobe at p eriastron passage. We also investigate the equivalent width Variations of t he 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 He II lambda 4686 and H alpha lines is consistent with a strong wind interact ion between the two stars, quite as predicted by current colliding wind mod els.