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

Oct, 2007
5 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 383 (2008) 750
e-Print:

Citations per year

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Abstract: (arXiv)
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.
  • BINARIES CLOSE
  • OPEN CLUSTERS
  • ASSOCIATIONS