HD 92206C: a new short-period massive binary in the Carina Nebula

Campillay, A.; Arias, J.; Barba, R.; Gamen, R.; Morrell, N.; Maíz Apellániz, J.; Walborn, N.; Sota, A.; Alfaro, E.
VI Reunion Anual Sociedad Chilena de Astronomia (SOCHIAS), held in Valparaiso, Chile, 7 - 9 November 2007, p. 63.


We present the discovery of a new double-lined spectroscopic massive binary in the Carina Nebula, as part of the results of the ``Spectroscopic Monitoring of Southern Galactic O and WN Stars'' survey. The high-resolution observations used in this study were obtained at La Silla, Las Campanas and CASLEO observatories, during the years 2006 and 2007. Together with their close massive neighbours, HD 92206A and B, the O-type system HD 92206C is one of the ionizing members of NGC 3324. Located at about 33 arcsec far away, this star forms a compact group with the close pair (separated by 5.4 arcsec) HD 92206A and B. Based on the new data, spectral types are derived for both components of HD 92206C, resulting a spectral classification of O7.5 V + B0 V. Finally, a period of 2.02 days with a mass-ratio of about 0.7 is determined from the radial velocity curve analysis.