Photometric Identification of the low-Mass Population of Orion OB1b I: The sigma Ori Cluster

Abstract

We report an optical photometric survey of 0.89 sq. degrees of the Orion OB1b association centered on sigma Ori. This region includes most of the sigma Ori cluster, the highest density region within Orion OB1b. We have developed a statistical procedure to identify the young, low-mass pre-main sequence population of the association. We estimate that the cluster has ~160 members in the mass range (0.2<M<1Msun). The cluster has a radius of ~3.5 pc and an estimated age of 2.5+/-0.3 Myr. We estimate that the total mass of the cluster is 225+/-30 Msun. This mass is similar to the estimated mass of the ~0.5 Myr old cluster NGC 2024. NGC 2024 and sigma Ori appear to be a well matched pair of clusters, except for the ~2 Myr difference in their ages.

arXiv commentTo be published in AJ

References in corpus (26)

• Embedded Clusters in Molecular Clouds
• The Initial Mass Function of Stars: Evidence for Uniformity in Variable Systems
• A Hipparcos census of the nearby OB associations
• Absolute dimensions of the M-type eclipsing binary YY Geminorum (Castor C): a challenge to evolutionary models in the lower main-sequence
• Dynamical Masses of T Tauri Stars and Calibration of PMS Evolution
• Young Low-Mass Stars and Brown Dwarfs in IC 348
• 2MASS Observations of the Perseus, Orion A, Orion B, and Monoceros R2 Molecular Clouds
• Near-Infrared Photometric Variability of Stars Toward the Orion A Molecular Cloud
• Infrared Photometry of Late-M, L, and T Dwarfs
• Infrared Spectra and Spectral Energy Distributions of Late-M- and L-Dwarfs
• A Test of Pre-Main Sequence Evolutionary Models Across the Stellar/Substellar Boundary Based on Spectra of the Young Quadruple GG Tau
• A Search for Very Low-mass Stars and Brown Dwarfs in the Young sigma Orionis Cluster
• Lithium and Halpha in stars and brown dwarfs of sigma Orionis
• A Disk Census for Young Brown Dwarfs
• The Substellar Mass Function in sigma Orionis
• X-rays in the Orion Nebula Cluster: Constraints on the origins of magnetic activity in pre-main sequence stars
• A Methane Isolated Planetary Mass Object in Orion
• Chandra X-ray Observatory Study of the Orion Nebula Cluster and BN/KL Region
• Explaining UXOR variability with self-shadowed disks
• Chandra X-ray Observation of the Orion Nebula Cluster. I Detection, Identification and Determination of X-ray Luminosities
• Identification of the ionizing source of NGC 2024
• Wide binaries in the Orion Nebula Cluster
• S Ori 70: Just a Foreground Field Brown Dwarf?
• An L'-band survey for circumstellar disks around low-mass stars in the young sigma Orionis cluster
• Spectroscopic estimate of surface gravity for a planetary member in the Sigma Ori cluster
• HST/NICMOS Observations of the Embedded Cluster in NGC 2024: Constraints on the IMF and Binary Fraction

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• Disk-Braking in Young Stars: Probing Rotation in Chamaeleon I and Taurus-Auriga
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• The NEMESIS Catalogue of Young Stellar Objects for the Orion Star Formation Complex. I. General description of data curation
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• Wide sigma Orionis binaries resolved by UKIDSS
• Finding the most variable stars in the Orion Belt with the All Sky Automated Survey
• Formation, evolution and multiplicity of brown dwarfs and giant exoplanets
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• The sub-solar Initial Mass Function in the Large Magellanic Cloud