SPATIALLY RESOLVING SUBSTRUCTURES WITHIN THE MASSIVE ENVELOPE AROUND AN INTERMEDIATE-MASS PROTOSTAR: MMS 6/OMC-3

Journal Article · Sun Jun 10 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/752/1/10· OSTI ID:22037118

Takahashi, Satoko; Ho, Paul T. P. ^[1]; Saigo, Kazuya; Tomida, Kengo ^[2]

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1. Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China)
2. National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)

With the Submillimeter Array, the brightest (sub)millimeter continuum source in the Orion Molecular Cloud-2/3 region, MMS 6, has been observed in the 850 {mu}m continuum emission with approximately 10 times better angular resolution than previous studies ( Almost-Equal-To 0.''3, Almost-Equal-To 120 AU at Orion). The deconvolved size, the mass, and the column density of MMS 6-main are estimated to be 0.''32 Multiplication-Sign 0.''29 (132 AU Multiplication-Sign 120 AU), 0.29 M{sub Sun }, and 2.1 Multiplication-Sign 10{sup 25} cm{sup -2}, respectively. The estimated extremely high mean number density, 1.5 Multiplication-Sign 10{sup 10} cm{sup -3}, suggests that MMS 6-main is likely optically thick at 850 {mu}m. We compare our observational data with three theoretical core models: prestellar core, protostellar core + disk-like structure, and first adiabatic core. These comparisons clearly show that the observational data cannot be modeled as a simple prestellar core with a gas temperature of 20 K. A self-luminous source is necessary to explain the observed flux density in the (sub)millimeter wavelengths. Our recent detection of a very compact and energetic outflow in the CO (3-2) and HCN (4-3) lines supports the presence of a protostar. We suggest that MMS 6 is one of the first cases of an intermediate-mass protostellar core at an extremely young stage. In addition to the MMS 6-main peak, we have also spatially resolved a number of spiky structures and sub-clumps, distributed over the central 1000 AU. The masses of these sub-clumps are estimated to be 0.066-0.073 M{sub Sun }, which are on the order of brown dwarf masses. Higher angular resolution and higher sensitivity observations with ALMA and EVLA will reveal the origin and nature of these structures such as whether they are originated from fragmentations, spiral arms, or inhomogeneity within the disk-like structures/envelope.

• OSTI ID: 22037118
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 752; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
CARBON MONOXIDE
COMPARATIVE EVALUATIONS
DENSITY
DETECTION
FAR INFRARED RADIATION
FLUX DENSITY
FRAGMENTATION
HYDROCYANIC ACID
MASS
PHOTON EMISSION
RESOLUTION
SENSITIVITY
STAR EVOLUTION
STARS