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The Herschel Orion Protostar Survey: Spectral Energy Distributions and Fits Using a Grid of Protostellar Models

Furlan, E. and Fischer, W. J. and Ali, B. and Stutz, A. M. and Stanke, T. and Tobin, J. J. and Megeath, S. T. and Osorio, M. and Hartmann, L. and Calvet, N. and Poteet, C. A. and Booker, J. and Manoj, P. and Watson, D. M. and Allen, L. (2016) The Herschel Orion Protostar Survey: Spectral Energy Distributions and Fits Using a Grid of Protostellar Models. Astrophysical Journal Supplement Series, 224 (1). Art. No. 5. ISSN 0067-0049.

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We present key results from the Herschel Orion Protostar Survey: spectral energy distributions (SEDs) and model fits of 330 young stellar objects, predominantly protostars, in the Orion molecular clouds. This is the largest sample of protostars studied in a single, nearby star formation complex. With near-infrared photometry from 2MASS, mid- and far-infrared data from Spitzer and Herschel, and submillimeter photometry from APEX, our SEDs cover 1.2–870 μm and sample the peak of the protostellar envelope emission at ~100 μm. Using mid-IR spectral indices and bolometric temperatures, we classify our sample into 92 Class 0 protostars, 125 Class I protostars, 102 flat-spectrum sources, and 11 Class II pre-main-sequence stars. We implement a simple protostellar model (including a disk in an infalling envelope with outflow cavities) to generate a grid of 30,400 model SEDs and use it to determine the best-fit model parameters for each protostar. We argue that far-IR data are essential for accurate constraints on protostellar envelope properties. We find that most protostars, and in particular the flat-spectrum sources, are well fit. The median envelope density and median inclination angle decrease from Class 0 to Class I to flat-spectrum protostars, despite the broad range in best-fit parameters in each of the three categories. We also discuss degeneracies in our model parameters. Our results confirm that the different protostellar classes generally correspond to an evolutionary sequence with a decreasing envelope infall rate, but the inclination angle also plays a role in the appearance, and thus interpretation, of the SEDs.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Furlan, E.0000-0001-9800-6248
Fischer, W. J.0000-0002-3747-2496
Stutz, A. M.0000-0003-2300-8200
Tobin, J. J.0000-0002-6195-0152
Megeath, S. T.0000-0001-7629-3573
Hartmann, L.0000-0003-1430-8519
Calvet, N.0000-0002-3950-5386
Additional Information:© 2016 The American Astronomical Society. Received 2015 August 21; accepted 2016 February 21; published 2016 May 6. Support for this work was provided by NASA through awards issued by JPL/Caltech. The work of W.J.F. was supported in part by an appointment to the NASA Postdoctoral Program at Goddard Space Flight Center, administered by Oak Ridge Associated Universities through a contract with NASA. J.J.T. acknowledges support provided by NASA through Hubble Fellowship grant #HST-HF-51300.01-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. J.J.T. acknowledges further support from grant 639.041.439 from the Netherlands Organisation for Scientific Research (NWO). The work of A. M.S. was supported by the Deutsche Forschungsgemeinschaft priority program 1573 (“Physics of the Interstellar Medium”). M.O. acknowledges support from MINECO (Spain) AYA2011-3O228-CO3-01 and AYA2014-57369-C3-3-P grants (co-funded with FEDER funds). We thank Thomas Robitaille for helpful discussions regarding the model grid and model parameters. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology (Caltech), under a contract with NASA; it is also based on observations made with the Herschel Space Observatory, a European Space Agency Cornerstone Mission with significant participation by NASA. The Herschel spacecraft was designed, built, tested, and launched under a contract to ESA managed by the Herschel/Planck Project team by an industrial consortium under the overall responsibility of the prime contractor Thales Alenia Space (Cannes), and including Astrium (Friedrichshafen) responsible for the payload module and for system testing at spacecraft level, Thales Alenia Space (Turin) responsible for the service module, and Astrium (Toulouse) responsible for the telescope, with in excess of 100 subcontractors. We also include data from the Atacama Pathfinder Experiment, a collaboration between the Max-Planck Institut für Radioastronomie, the European Southern Observatory, and the Onsala Space Observatory. 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/Caltech, funded by NASA and the NSF.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASA Postdoctoral ProgramUNSPECIFIED
NASA Hubble Fellowship grantHST-HF-51300.01-A
NASANAS 5-26555
Netherlands Organisation for Scientific Research (NWO)639.041.439
Deutsche Forschungsgemeinschaft (DFG)1573
Ministerio de Economía y Competitividad (MINECO)AYA2011-3O228-CO3-01
Ministerio de Economía y Competitividad (MINECO)AYA2014-57369-C3-3-P
Subject Keywords:circumstellar matter; infrared: stars; methods: data analysis; stars: formation; stars: protostars
Record Number:CaltechAUTHORS:20160624-081059594
Persistent URL:
Official Citation:E. Furlan et al 2016 ApJS 224 5
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:68648
Deposited By: Ruth Sustaita
Deposited On:24 Jun 2016 17:08
Last Modified:20 Mar 2019 17:16

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