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The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. IV. Unveiling the Embedded Intermediate-Mass Protostar and Disk within OMC2-FIR3/HOPS-370

Tobin, John J. and Sheehan, Patrick D. and Reynolds, Nickalas and Megeath, S. Thomas and Osorio, Mayra and Anglada, Guillem and Díaz-Rodríguez, Ana Karla and Furlan, Elise and Kratter, Kaitlin M. and Offner, Stella S. R. and Looney, Leslie W. and Kama, Mihkel and Li, Zhi-Yun and van ’t Hoff, Merel L. R. and Sadavoy, Sarah I. and Karnath, Nicole (2020) The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. IV. Unveiling the Embedded Intermediate-Mass Protostar and Disk within OMC2-FIR3/HOPS-370. Astrophysical Journal, 905 (2). Art. No. 162. ISSN 1538-4357.

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We present ALMA (0.87 and 1.3 mm) and VLA (9 mm) observations toward the candidate intermediate-mass protostar OMC2-FIR3 (HOPS-370; L_(bol) ~ 314 L_⊙) at ~0."1 (40 au) resolution for the continuum emission and ~0."25 (100 au) resolution of nine molecular lines. The dust continuum observed with ALMA at 0.87 and 1.3 mm resolves a near edge-on disk toward HOPS-370 with an apparent radius of ~100 au. The VLA observations detect both the disk in dust continuum and free–free emission extended along the jet direction. The ALMA observations of molecular lines (H₂CO, SO, CH₃OH, ¹³CO, C¹⁸O, NS, and H¹³CN) reveal rotation of the apparent disk surrounding HOPS-370 orthogonal to the jet/outflow direction. We fit radiative transfer models to both the dust continuum structure of the disk and molecular line kinematics of the inner envelope and disk for the H₂CO, CH₃OH, NS, and SO lines. The central protostar mass is determined to be ~2.5 M_⊙ with a disk radius of ~94 au, when fit using combinations of the H₂CO, CH₃OH, NS, and SO lines, consistent with an intermediate-mass protostar. Modeling of the dust continuum and spectral energy distribution yields a disk mass of 0.035 M_⊙ (inferred dust+gas) and a dust disk radius of 62 au; thus, the dust disk may have a smaller radius than the gas disk, similar to Class II disks. In order to explain the observed luminosity with the measured protostar mass, HOPS-370 must be accreting at a rate of (1.7−3.2) × 10⁻⁵ M_⊙ yr⁻¹.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Tobin, John J.0000-0002-6195-0152
Sheehan, Patrick D.0000-0002-9209-8708
Reynolds, Nickalas0000-0002-9239-6422
Megeath, S. Thomas0000-0001-7629-3573
Osorio, Mayra0000-0002-6737-5267
Anglada, Guillem0000-0002-7506-5429
Díaz-Rodríguez, Ana Karla0000-0001-9112-6474
Furlan, Elise0000-0001-9800-6248
Kratter, Kaitlin M.0000-0001-5253-1338
Offner, Stella S. R.0000-0003-1252-9916
Looney, Leslie W.0000-0002-4540-6587
Kama, Mihkel0000-0003-0065-7267
van ’t Hoff, Merel L. R.0000-0002-2555-9869
Sadavoy, Sarah I.0000-0001-7474-6874
Karnath, Nicole0000-0003-3682-854X
Alternate Title:The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars IV. Unveiling the Embedded Intermediate-Mass Protostar and Disk within OMC2-FIR3/HOPS-370
Additional Information:© 2020. The American Astronomical Society. Received 2020 September 24; revised 2020 October 27; accepted 2020 October 27; published 2020 December 24. The authors thank the anonymous referee for a constructive report that improved the quality of the manuscript. The authors wish to acknowledge useful discussions with L. Hartmann and J. Bae about the results. J.J.T. acknowledges support from grant AST-1814762 from the National Science Foundation and past support from the Homer L. Dodge Endowed Chair at the University of Oklahoma. P.D.S is supported by a National Science Foundation Astronomy & Astrophysics Postdoctoral Fellowship under Award No. 2001830. G.A., M.O., and A.K.D.-R. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the AYA2017-84390-C2-1-R grant (co-funded by FEDER) and through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). Z.Y.L. is supported in part by NASA 80NSSC18K1095 and NSF AST-1716259. M.K. gratefully acknowledges funding by the University of Tartu ASTRA project 2014-2020.4.01.16-0029 KOMEET "Benefits for Estonian Society from Space Research and Application," financed by the EU European Regional Development Fund. M.L.R.H. acknowledges support from the Michigan Society of Fellows. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2015.1.00041.S and ADS/JAO.ALMA#2017.1.00419.S. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. These results are based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium (ARC). We wish to thank the APO 3.5 m telescope operators in their assistance in obtaining these data. Access to the APO 3.5 m telescope is funded by the University of Oklahoma and the Homer L. Dodge Endowed Chair. This research made use of APLpy, an open-source plotting package for Python hosted at This research made use of Astropy, a community-developed core Python package for Astronomy (Astropy Collaboration, 2013) Facilities: ALMA - Atacama Large Millimeter Array, VLA - , TripleSpec/ARC 3.5 m. - Software: Astropy (; Greenfield et al. 2013; Astropy Collaboration et al. 2018), APLpy (; Robitaille & Bressert 2012), CASA (; McMullin et al. 2007), pdspy (; Sheehan & Eisner 2017; Sheehan et al. 2019), GALARIO (; Tazzari et al. 2018), RADMC-3D (; Dullemond et al. 2012).
Funding AgencyGrant Number
University of OklahomaUNSPECIFIED
NSF Astronomy and Astrophysics FellowshipAST-2001830
Ministerio de Ciencia, Innovación y Universidades (MCIU)AYA2017-84390-C2-1-R
Fondo Europeo de Desarrollo Regional (FEDER)UNSPECIFIED
Severo OchoaSEV-2017-0709
University of Tartu2014-2020.4.01.16-0029
European Regional Development FundUNSPECIFIED
Michigan Society of FellowsUNSPECIFIED
Subject Keywords:Protostars ; Young stellar objects ; Interstellar medium ; Interstellar molecules
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Protostars (1302); Young stellar objects (1834); Interstellar medium (847); Interstellar molecules (849)
Record Number:CaltechAUTHORS:20201224-134252426
Persistent URL:
Official Citation:John J. Tobin et al 2020 ApJ 905 162
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107289
Deposited By: George Porter
Deposited On:04 Jan 2021 17:19
Last Modified:04 Jan 2021 17:19

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