Optical spectroscopy of X-Mega targets : II. The massive double-lined O-type binary HD93205

• Autores: 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
• Año de publicación: 2001
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Astronómicas; Astrofísica; binaries: general; stars: early-type; stars: individual: HD 93205; X-rays: stars
• Institución: Universidad Nacional de La Plata

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