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Title: Star Formation Under the Outflow: The Discovery of a Non-thermal Jet from OMC-2 FIR 3 and Its Relationship to the Deeply Embedded FIR 4 Protostar

Abstract

We carried out multiwavelength (0.7–5 cm), multi-epoch (1994–2015) Very Large Array (VLA) observations toward the region enclosing the bright far-IR sources FIR 3 (HOPS 370) and FIR 4 (HOPS 108) in OMC-2. We report the detection of 10 radio sources, 7 of them identified as young stellar objects. We image a well-collimated radio jet with a thermal free–free core (VLA 11) associated with the Class I intermediate-mass protostar HOPS 370. The jet features several knots (VLA 12N, 12C, 12S) of non-thermal radio emission (likely synchrotron from shock-accelerated relativistic electrons) at distances of ∼7500–12,500 au from the protostar, in a region where other shock tracers have been previously identified. These knots are moving away from the HOPS 370 protostar at ∼100 km s{sup −1}. The Class 0 protostar HOPS 108, which itself is detected as an independent, kinematically decoupled radio source, falls in the path of these non-thermal radio knots. These results favor the previously proposed scenario in which the formation of HOPS 108 is triggered by the impact of the HOPS 370 outflow with a dense clump. However, HOPS 108 has a large proper motion velocity of ∼30 km s{sup −1}, similar to that of other runaway stars in Orion,more » whose origin would be puzzling within this scenario. Alternatively, an apparent proper motion could result because of changes in the position of the centroid of the source due to blending with nearby extended emission, variations in the source shape, and/or opacity effects.« less

Authors:
; ; ;  [1];  [2]; ; ;  [3];  [4];  [5];  [6];  [7];  [8]; ;  [9];  [10];  [11]
  1. Instituto de Astrofísica de Andalucía (CSIC) Glorieta de la Astronomía s/n E-18008 Granada (Spain)
  2. Ritter Astrophysical Research Center, Department of Physics and Astronomy University of Toledo 2801 West Bancroft Street Toledo, OH 43606 (United States)
  3. Instituto de Radioastronomía y Astrofísica, UNAM Apartado Postal 3-72 (Xangari), 58089 Morelia, Michoacán (Mexico)
  4. Homer L. Dodge Department of Physics and Astronomy University of Oklahoma, Norman, OK 73019 (United States)
  5. Department of Astronomy, University of Concepción Concepción (Chile)
  6. IPAC, Mail Code 314-6, Caltech 1200 E. California Boulevard, Pasadena, CA 91125 (United States)
  7. Space Telescope Science Institute 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  8. Tata Institute of Fundamental Research Homi Bhabha Road, Mumbai 400 005 (India)
  9. European Space Astronomy Center, ESA P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain)
  10. European Southern Observatory Garching bei München (Germany)
  11. Department of Physics and Astronomy, University of Rochester Rochester, NY 14627 (United States)
Publication Date:
OSTI Identifier:
22663651
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 840; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DETECTION; DISTANCE; ELECTRONS; EMISSION; MASS; MIXING; OPACITY; PROPER MOTION; PROTOSTARS; RELATIVISTIC RANGE; STARS; SYNCHROTRON RADIATION; VELOCITY

Citation Formats

Osorio, Mayra, Díaz-Rodríguez, Ana K., Anglada, Guillem, Gómez, José F., Megeath, S. Thomas, Rodríguez, Luis F., Loinard, Laurent, Carrasco-González, Carlos, Tobin, John J., Stutz, Amelia M., Furlan, Elise, Fischer, William J., Manoj, P., González-García, Beatriz, Vavrek, Roland, Stanke, Thomas, and Watson, Dan M., E-mail: osorio@iaa.es. Star Formation Under the Outflow: The Discovery of a Non-thermal Jet from OMC-2 FIR 3 and Its Relationship to the Deeply Embedded FIR 4 Protostar. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA6975.
Osorio, Mayra, Díaz-Rodríguez, Ana K., Anglada, Guillem, Gómez, José F., Megeath, S. Thomas, Rodríguez, Luis F., Loinard, Laurent, Carrasco-González, Carlos, Tobin, John J., Stutz, Amelia M., Furlan, Elise, Fischer, William J., Manoj, P., González-García, Beatriz, Vavrek, Roland, Stanke, Thomas, & Watson, Dan M., E-mail: osorio@iaa.es. Star Formation Under the Outflow: The Discovery of a Non-thermal Jet from OMC-2 FIR 3 and Its Relationship to the Deeply Embedded FIR 4 Protostar. United States. doi:10.3847/1538-4357/AA6975.
Osorio, Mayra, Díaz-Rodríguez, Ana K., Anglada, Guillem, Gómez, José F., Megeath, S. Thomas, Rodríguez, Luis F., Loinard, Laurent, Carrasco-González, Carlos, Tobin, John J., Stutz, Amelia M., Furlan, Elise, Fischer, William J., Manoj, P., González-García, Beatriz, Vavrek, Roland, Stanke, Thomas, and Watson, Dan M., E-mail: osorio@iaa.es. Mon . "Star Formation Under the Outflow: The Discovery of a Non-thermal Jet from OMC-2 FIR 3 and Its Relationship to the Deeply Embedded FIR 4 Protostar". United States. doi:10.3847/1538-4357/AA6975.
@article{osti_22663651,
title = {Star Formation Under the Outflow: The Discovery of a Non-thermal Jet from OMC-2 FIR 3 and Its Relationship to the Deeply Embedded FIR 4 Protostar},
author = {Osorio, Mayra and Díaz-Rodríguez, Ana K. and Anglada, Guillem and Gómez, José F. and Megeath, S. Thomas and Rodríguez, Luis F. and Loinard, Laurent and Carrasco-González, Carlos and Tobin, John J. and Stutz, Amelia M. and Furlan, Elise and Fischer, William J. and Manoj, P. and González-García, Beatriz and Vavrek, Roland and Stanke, Thomas and Watson, Dan M., E-mail: osorio@iaa.es},
abstractNote = {We carried out multiwavelength (0.7–5 cm), multi-epoch (1994–2015) Very Large Array (VLA) observations toward the region enclosing the bright far-IR sources FIR 3 (HOPS 370) and FIR 4 (HOPS 108) in OMC-2. We report the detection of 10 radio sources, 7 of them identified as young stellar objects. We image a well-collimated radio jet with a thermal free–free core (VLA 11) associated with the Class I intermediate-mass protostar HOPS 370. The jet features several knots (VLA 12N, 12C, 12S) of non-thermal radio emission (likely synchrotron from shock-accelerated relativistic electrons) at distances of ∼7500–12,500 au from the protostar, in a region where other shock tracers have been previously identified. These knots are moving away from the HOPS 370 protostar at ∼100 km s{sup −1}. The Class 0 protostar HOPS 108, which itself is detected as an independent, kinematically decoupled radio source, falls in the path of these non-thermal radio knots. These results favor the previously proposed scenario in which the formation of HOPS 108 is triggered by the impact of the HOPS 370 outflow with a dense clump. However, HOPS 108 has a large proper motion velocity of ∼30 km s{sup −1}, similar to that of other runaway stars in Orion, whose origin would be puzzling within this scenario. Alternatively, an apparent proper motion could result because of changes in the position of the centroid of the source due to blending with nearby extended emission, variations in the source shape, and/or opacity effects.},
doi = {10.3847/1538-4357/AA6975},
journal = {Astrophysical Journal},
number = 1,
volume = 840,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2017},
month = {Mon May 01 00:00:00 EDT 2017}
}
  • We use mid-infrared to submillimeter data from the Spitzer, Herschel, and Atacama Pathfinder Experiment telescopes to study the bright submillimeter source OMC-2 FIR 4. We find a point source at 8, 24, and 70 μm, and a compact, but extended source at 160, 350, and 870 μm. The peak of the emission from 8 to 70 μm, attributed to the protostar associated with FIR 4, is displaced relative to the peak of the extended emission; the latter represents the large molecular core the protostar is embedded within. We determine that the protostar has a bolometric luminosity of 37 L {submore » ☉}, although including more extended emission surrounding the point source raises this value to 86 L {sub ☉}. Radiative transfer models of the protostellar system fit the observed spectral energy distribution well and yield a total luminosity of most likely less than 100 L {sub ☉}. Our models suggest that the bolometric luminosity of the protostar could be as low as 12-14 L {sub ☉}, while the luminosity of the colder (∼20 K) extended core could be around 100 L {sub ☉}, with a mass of about 27 M {sub ☉}. Our derived luminosities for the protostar OMC-2 FIR 4 are in direct contradiction with previous claims of a total luminosity of 1000 L {sub ☉}. Furthermore, we find evidence from far-infrared molecular spectra and 3.6 cm emission that FIR 4 drives an outflow. The final stellar mass the protostar will ultimately achieve is uncertain due to its association with the large reservoir of mass found in the cold core.« less
  • We present subarcsecond resolution HCN (4-3) and CO (3-2) observations made with the Submillimeter Array, toward an extremely young intermediate-mass protostellar core, MMS 6-main, located in the Orion Molecular Cloud 3 region (OMC-3). We have successfully imaged a compact molecular outflow lobe ( Almost-Equal-To 1000 AU) associated with MMS 6-main, which is also the smallest molecular outflow ever found in the intermediate-mass protostellar cores. The dynamical timescale of this outflow is estimated to be {<=}100 yr. The line width dramatically increases downstream at the end of the molecular outflow ({Delta}v {approx} 25 km s{sup -1}) and clearly shows the bow-shock-typemore » velocity structure. The estimated outflow mass ( Almost-Equal-To 10{sup -4} M{sub Sun }) and outflow size are approximately two to four orders and one to three orders of magnitude smaller, respectively, while the outflow force ( Almost-Equal-To 10{sup -4} M{sub Sun} km s{sup -1} yr{sup -1}) is similar, compared to the other molecular outflows studied in OMC-2/3. These results show that MMS 6-main is a protostellar core at the earliest evolutionary stage, most likely shortly after the second core formation.« less
  • The SCUBA polarized 850 {mu}m thermal emission data of the OMC-2 region in Orion A are added to and homogeneously reduced with data already available in the OMC-3 region. The data set shows that OMC-2 is a region generally less polarized than OMC-3. Where coincident, most of the 850 {mu}m polarization pattern is similar to that measured in 350 {mu}m polarization data. Only 850 {mu}m polarimetry data have been obtained in and around MMS7, FIR1 and FIR2, and in the region south of FIR6. A realignment of the polarization vectors with the filament can be seen near FIR1 in themore » region south of OMC-3. An analysis shows that the energy injected by CO outflows and H{sub 2} jets associated with OMC-2 and OMC-3 does not appear to alter the polarization patterns at a scale of the 14'' resolution beam. A second-order structure function analysis of the polarization position angles shows that OMC-2 is a more turbulent region than OMC-3. OMC-3 appears to be a clear case of a magnetically dominated region with respect to the turbulence. However, for OMC-2 it is not clear that this is the case. A more in-depth analysis of five regions displayed along OMC-2/3 indicates a decrease of the mean polarization degree and an increase of the turbulent angular dispersion from north to south. A statistical analysis suggests the presence of two depolarization regimes in our maps: one regime including the effects of the cores, the other one excluding it.« less
  • Subarcsecond (0.''5) images of H{sub 2}CO and CCH line emission have been obtained in the 0.8 mm band toward the low-mass protostar IRAS 15398–3359 in the Lupus 1 cloud as one of the Cycle 0 projects of the Atacama Large Millimeter/Submillimeter Array. We have detected a compact component concentrated in the vicinity of the protostar and a well-collimated outflow cavity extending along the northeast-southwest axis. The inclination angle of the outflow is found to be about 20°, or almost edge-on, based on the kinematic structure of the outflow cavity. This is in contrast to previous suggestions of a more pole-onmore » geometry. The centrally concentrated component is interpreted by use of a model of the infalling rotating envelope with the estimated inclination angle and the mass of the protostar is estimated to be less than 0.09 M {sub ☉}. Higher spatial resolution data are needed to infer the presence of a rotationally supported disk for this source, hinted at by a weak high-velocity H{sub 2}CO emission associated with the protostar.« less