Main-Seqence Fitting Distance to the sigma Ori Cluster

Abstract

The sigma Ori cluster is an unbound aggregate of a few hundred young, low-mass stars centered on the multiple system sigma Ori. This cluster is of great interest because it is at an age when roughly half of the stars have lost their protoplanetary disks, and the cluster has a very large population of brown dwarfs. One of the largest sources of uncertainty in the properties of the cluster is that the distance is not well known. The directly measured Hipparcos distance to sigma Ori AB is 350 (+120,-90) pc. On the other hand, the distance to the Orion OB1b subgroup (of which sigma Ori is thought to be a member), 473+/-40 pc, is far better determined, but it is an indirect estimate of the cluster's distance. Also, Orion OB1b may have a depth of 40 pc along our line of sight. We use main sequence fitting to 9 main sequence cluster members to estimate a best fit distance of 420+/-30 pc, assuming a metallicity of -0.16+/-0.11 or 444 pc assuming solar metallicity. A distance as close as 350 pc is inconsistent with the observed brightnesses of the cluster members. At the best fit distance, the age of the cluster is 2-3 Myrs.

Accepted by AJ

References in corpus (18)

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Cited by in corpus (53)

• The Galactic O-Star Spectroscopic Survey. I. Classification System and Bright Northern Stars in the Blue-Violet at R~2500
• An ALMA Survey of Protoplanetary Disks in the $\sigma$ Orionis Cluster
• The APOGEE-2 Survey of the Orion Star Forming Complex II: Six-dimensional structure
• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• Protoplanetary disc truncation mechanisms in stellar clusters: comparing external photoevaporation and tidal encounters
• The Spitzer Space Telescope Survey of the Orion A and B Molecular Clouds II: the Spatial Distribution and Demographics of Dusty Young Stellar Objects
• New isolated planetary mass objects and the stellar and substellar mass function of the sigma Orionis cluster
• Catalogue of particle-accelerating colliding-wind binaries
• Debris Disks in the Upper Scorpius OB Association
• Are pre-main-sequence stars older than we thought?
• Precision photometric monitoring of very low mass Sigma Orionis cluster members: variability and rotation at a few Myr
• Orbits, Distance, and Stellar Masses of the Massive Triple Star Sigma Orionis
• Candidate free-floating super-Jupiters in the young sigma Orionis open cluster
• Orbital and physical properties of the $\sigma$ Ori Aa,Ab,B triple system
• Trigonometric parallaxes of young field L dwarfs
• A spectroscopic census in young stellar regions: the Sigma Orionis cluster
• A universal spin-mass relation for brown dwarfs and planets
• MOST Observations of sigma Ori E: Challenging the Centrifugal Breakout Narrative
• Hot spots and a clumpy disk: Variability of brown dwarfs and stars in the young Sigma Ori cluster
• A deep look into the cores of young clusters I. sigma-Orionis
• Spitzer Observations of the Lambda Orionis cluster I: the frequency of young debris disks at 5 Myr
• Chemical abundances of late-type pre-main sequence stars in the $\sigma$-Orionis cluster
• Polycyclic Aromatic Hydrocarbon emission in Spitzer/IRS maps I: Catalog and simple diagnostics
• The Gaia-ESO Survey: the first abundance determination of the pre-main-sequence cluster Gamma Velorum
• Rotation Periods of Young Brown Dwarfs: K2 Survey in Upper Scorpius
• A SCUBA-2 850 micron survey of protoplanetary discs in the sigma Orionis cluster
• A third massive star component in the σ Orionis AB system
• Optical and Near-Infrared Spectra of sigma Orionis Isolated Planetary-mass Objects
• Spectroscopic Assessment of WISE-based Young Stellar Object Selection
• Search and characterization of T-type planetary mass candidates in the sigma Orionis cluster
• A Pulsation Search Among Young Brown Dwarfs and Very Low Mass Stars
• Mapping young stellar populations towards Orion with Gaia DR1
• Low-resolution spectroscopy and spectral energy distributions of selected sources towards sigma Orionis
• Testing external photoevaporation in the $\sigma$-Orionis cluster with spectroscopy and disk mass measurements
• An Infrared Census of Star Formation in the Horsehead Nebula
• Stars and brown dwarfs in the sigma Orionis cluster. II. A proper motion study
• New deep XMM-Newton observations to the west of the sigma Orionis cluster
• A novel survey for young substellar objects with the W-band filter VI: Spectroscopic census of sub-stellar members and the IMF of $\sigma$ Orionis cluster
• Young brown dwarfs at high cadence: Warm Spitzer time series monitoring of very low mass Sigma Orionis cluster members
• Stars and brown dwarfs in the sigma Orionis cluster. IV. IDS/INT and OSIRIS/GTC spectroscopy and Gaia DR2 astrometry
• HRC-I/Chandra X-ray observations towards sigma Orionis
• X-ray variability of sigma Orionis young stars with ROSAT
• Variability in young very low mass stars: Two surprises from spectrophotometric monitoring
• Characterization of the known T type dwarfs towards the Sigma Orionis cluster
• Sigma Orionis IRS1 A and B: A Binary Containing a Proplyd
• Photometric variability of the Herbig Ae star HD 37806
• The influence of metallicity on a combined stellar and disk evolution
• XMM-Newton observations of the young open cluster around lambda Orionis
• A TGAS/Gaia DR1 parallactic distance to the sigma Orionis cluster
• News from Gaia on sigma Ori E: a case study for the wind magnetic braking process
• Formation, evolution and multiplicity of brown dwarfs and giant exoplanets
• A review on substellar objects beyond the deuterium burning mass limit: planets, brown dwarfs or what?
• A deep staring campaign in the Sigma Orionis cluster. Variability in substellar members