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 1.7 kpc. 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 ≤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.
Additional Information
© 2019 The American Astronomical Society. Received 2019 July 30; revised 2019 October 10; accepted 2019 October 10; published 2019 November 19. The first two authors contributed equally to this study. We benefited from crucial earlier work by Matt Povich (California State Polytechnic University, Pomona), valuable discussion with Daniel Apai (Arizona), and the insightful comments of an anonymous referee. This work was supported by NASA grants GO7-18001X and the Chandra ACIS Team contract SV474018 (G. Garmire and L. Townsley, Principal Investigators), issued by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8-03060. The Guaranteed Time Observations (GTO) data used here were selected by the ACIS Instrument Principal Investigator, Gordon P. Garmire, of the Huntingdon Institute for X-ray Astronomy, LLC, which is under contract to the Smithsonian Astrophysical Observatory; Contract SV2-82024. This work has also made use of data from the European Space Agency (ESA) mission Gaia, processed by the Gaia Data Processing and Analysis Consortium (DPAC). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.ha This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This research has made use of NASA's Astrophysics Data System Bibliographic Services and SAOImage DS9 software developed by Smithsonian Astrophysical Observatory.Attached Files
Published - Getman_2019_AJ_158_235.pdf
Submitted - 1910.04873.pdf
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Additional details
- Eprint ID
- 99961
- Resolver ID
- CaltechAUTHORS:20191120-143150381
- GO7-18001X
- NASA
- SV474018
- NASA
- NAS8-03060
- NASA
- SV2-82024
- Smithsonian Astrophysical Observatory
- Gaia Multilateral Agreement
- NSF
- Created
-
2019-11-20Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)