Four massive O-type eclipsing binaries.

E. FERNÁNDEZ LAJÚS; V. NIEMELA.

Prague, Czech Republic

Simposio; Binary Stars as Critical Tools and Tests in Contemporary Astrophysics, International Astronomical Union. Symposium no. 240; 2006

International Astronomical Union

We have determined fundamental properties of four eclipsing massive O-type binaries. Three of these eclipsing binaries, namely FO15, CPD-59 2603 and CPD-59 2635 are members of the young open cluster Tr16 in the Carina Nebula. The fourth eclipsing binary, LS 1135, is located in the OB association Bochum 7. Light curves and radial velocities were analyzed with the Wilson-Devinney code. We find all four systems to be detached. The eclipsing binaries in the Carina Nebula have properties of stars which have recently arrived to ZAMS, as we find them to have smaller radii and luminosities than "normal" O-type stars. The properties of the components of LS1135 correspond to "normal" massive stars.