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

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.

MNRAS, accepted

References in corpus (12)

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• Spatial distribution of stars and brown dwarfs in sigma Orionis
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Cited by in corpus (22)

• Orbits, Distance, and Stellar Masses of the Massive Triple Star Sigma Orionis
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• Orbital and physical properties of the $\sigma$ Ori Aa,Ab,B triple system
• High-Resolution Chandra X-ray Imaging and Spectroscopy of the Sigma Orionis Cluster
• A spectroscopic census in young stellar regions: the Sigma Orionis cluster
• A deep look into the cores of young clusters I. sigma-Orionis
• Young stars and brown dwarfs surrounding Alnilam (eps Ori) and Mintaka (del Ori)
• A Herschel view of protoplanetary disks in the $\sigma$ Ori cluster
• A Near-infrared Survey of UV-excited Molecular Hydrogen in Photodissociation Regions
• System IMF of the 25 Ori Group from Planetary-Mass Objects to Intermediate/High-Mass Stars
• Low-resolution spectroscopy and spectral energy distributions of selected sources towards sigma Orionis
• A revisit to agglomerates of early-type Hipparcos stars
• SDSS-V Local Volume Mapper (LVM): A Glimpse into Orion
• A bimodal dust grain distribution in the IC 434 HII region
• New deep XMM-Newton observations to the west of the sigma Orionis cluster
• Very low-luminosity Class I/Flat outflow sources in sigma Orionis
• Orion revisited III. The Orion Belt population
• Characterization of the known T type dwarfs towards the Sigma Orionis cluster
• The Occurrence Rate of Quiescent Radio Emission for Ultracool Dwarfs using a Generalized Semi-Analytical Bayesian Framework
• Models for the Formation of Massive Stars
• X-ray emission from stellar jets by collision against high-density molecular clouds: an application to HH 248