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Optical spectroscopy of X-Mega targets in the Carina Nebula. II. The massive double-lined O-type binary HD 93205

N. I. Morrell·R. H. Barba·V. S. Niemela·M. A. Corti·J. F. Albacete Colombo·G. Rauw·M. Corcoran·T. Morel·J. -F. Bertrand·A. F. J. Moffat·N. St-Louis
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Abstract

A new high-quality set of orbital parameters for the O-type spectroscopic binary HD93205 has been obtained combining echelle and coude CCD observations. The radial velocity orbits derived from the HeII 4686 A (primary component) and HeI 4471 A (secondary component) absorption lines yield semiamplitudes of 133 +/- 2 and 314 +/- 2 km/s for each binary component, resulting in minimum masses of 31 and 13 Msol (q = 0.42). We also confirm for the binary components the spectral classification of O3V+O8V previously assigned. Assuming for the O8V component a ``normal'' mass of 22 - 25 Msol we would derive for the primary O3V a mass of ``only'' 52 - 60 Msol and an inclination of about 55 degrees for the orbital plane. We have also determined for the first time a period of apsidal motion for this system, namely 185 +/- 16 years 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.

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N. I. Morrell, R. H. Barba, V. S. Niemela, M. A. Corti, J. F. Albacete Colombo, G. Rauw, M. Corcoran, T. Morel, J. -F. Bertrand, A. F. J. Moffat, N. St-Louis. 2001-05-01. Optical spectroscopy of X-Mega targets in the Carina Nebula. II. The massive double-lined O-type binary HD 93205. https://doi.org/10.1046/j.1365-8711.2001.04500.x

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