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arXiv · 0710.3541

Dynamical parallax of sigma Ori AB: mass, distance and age

Jose A. Caballero
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Abstract

The massive OB-type binary sigma Ori AB is in the centre of the very young sigma Orionis cluster. I have computed the most probable distances and masses of the binary for several ages using a dynamical parallax-like method. It incorporates the BVRIH-band apparent magnitudes of both components, precise orbital parameters, interstellar extinction and a widely used grid of stellar models from the literature, the Kepler's third law and a chi^2 minimisation. The derived distance is 334^(+25)_(-22) pc for an age of 3+/-2 Ma; larger ages and distances are unlikely. The masses of the primary and the secondary lie on the approximate intervals 16-20 and 10-12 Msol, respectively. I also discuss the possibility of sigma Ori AB being a triple system at ~385 pc. These results will help to constrain the properties of young stars and substellar objects in the sigma Orionis cluster.

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Jose A. Caballero. 2007-10-18. Dynamical parallax of sigma Ori AB: mass, distance and age. https://doi.org/10.1111/j.1365-2966.2007.12614.x

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