IRAS 09002-4732: A Laboratory for the Formation of Rich Stellar Clusters

Abstract

IRAS 09002-4732 is a poorly studied embedded cluster of stars in the Vela Molecular Ridge at a distance of 1.7kpc. Deep observations with the Chandra X-ray Observatory, combined with existing optical and infrared surveys, produce a catalog of 441 probable pre-main sequence members of the region. The stellar spatial distribution has two components: most stars reside in a rich, compact, elliptical cluster, but a minority reside within a molecular filament several parsecs long that straddles the cluster. The filament has active distributed star formation with dozens of unclustered protostars. The cluster pre-main sequence population is $\le 0.8$ Myr old and deeply embedded; its most massive member is extremely young producing an ultracompact H II region. The cluster total population deduced from the X-ray luminosity function is surprisingly rich, twice that of the Orion Nebula Cluster. The cluster core is remarkably dense where strong N-body interactions should be occurring; its Initial Mass Function may be deficient in massive stars. We infer that IRAS 09002-4732 is a rare case where a rich cluster is forming today in a molecular filament, consistent with astrophysical models of cluster formation in clouds that involve the hierarchical formation and merging of groups in molecular filaments.

33 pages, 11 figures, 3 machine readable tables. To appear in The Astronomical Journal

References in corpus (18)

• The Gaia mission
• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• Inefficient star formation through turbulence, magnetic fields and feedback
• The Spatial Structure of Young Stellar Clusters. I. Subclusters
• The gas-to-extinction ratio and the gas distribution in the Galaxy
• Age Gradients in the Stellar Populations of Massive Star Forming Regions Based on a New Stellar Chronometer
• The RMS Survey: Mid-Infrared Observations of Candidate Massive YSOs in the Southern Hemisphere
• The three dimensional dynamic structure of the inner Orion Nebula
• The Diverse Stellar Populations of the W3 Star Forming Complex
• The Spatial Structure of Young Stellar Clusters. II. Total Young Stellar Populations
• Herschel Observations of the W3 GMC: Clues to the Formation of Clusters of High-Mass Stars
• Gaia Stellar Kinematics in the Head of the Orion A Cloud: Runaway Stellar Groups and Gravitational Infall
• The JCMT Gould Belt Survey: A First Look at IC 5146
• A multi-wavelength observation and investigation of six infrared dark clouds
• The Structure of the Young Star Cluster NGC 6231. II. Structure, Formation, and Fate
• Star Formation Activity in the Long, Filamentary Infrared Dark Cloud G53.2
• On the dynamical evolution of the Orion Trapezium
• Young Stellar Populations in MYStIX Star Forming Regions: Candidate Protostars

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• A Low Frequency Pilot Survey of Southern HII Regions in the Vela Constellation
• Physical Properties and Kinematics of Dense Cores Associated with Regions of Massive Star Formation from the Southern Sky
• Dust Temperature Profiles in Dense Cores Associated With Massive Star-Forming Regions