Articulo
Optical spectroscopy of X-Mega targets : II. The massive double-lined O-type binary HD93205
Autor
Morrell, Nidia Irene
Barbá, Rodolfo Héctor
Niemelä, Virpi Sinikka
Corti, Mariela Alejandra
Albacete Colombo, Juan Facundo
Rauw, G.
Corcoran, Michael
Morel, T.
Bertrand, J. F.
Moffat, Anthony
St-Louis, Nicole
Institución
Resumen
A new high-quality set of orbital parameters for the O-type spectroscopic binary HD 93205 has been obtained combining échelle and coudé CCD observations. The radial velocity orbits derived from the He iiλ4686 Å (primary component) and He iλ4471 Å (secondary component) absorption lines yield semi-amplitudes of 133±2 and 314±2 km s−1 for each binary component, resulting in minimum masses of 31 and 13 M⊙(q=0.42). We also confirm for the binary components the spectral classification of O3 V+ O8 V previously assigned. Assuming for the O8 V component a ‘normal’ mass of 22–25 M⊙ we would derive for the primary O3 V a mass of ‘only’52–60 M⊙ and an inclination of about 55° for the orbital plane. We have also determined for the first time a period of apsidal motion for this system, namely 185±16 yr using all available radial velocity data sets of HD 93205 (from 1975 to 1999). Phase-locked variations of the X-ray emission of HD 93205 consisting of a rise of the observed X-ray flux near periastron passage are also discussed. Facultad de Ciencias Astronómicas y Geofísicas