Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evolutionary Status of Brightest and Youngest Source in the Orion
  Molecular Cloud-3 Region   The brightest continuum source in the Orion Molecular Cloud-3 region (OMC-3),
MMS 6, was observed with the Very Large Array (VLA), the Nobeyama Millimeter
Array (NMA), and the Submillimeter Array (SMA). Our data were supplemented by
near- to mid-infrared archival data taken by Spitzer Space Telescope. The
compact continuum source, MMS 6-main, was detected with an H_2 mass of 3.0 Msun
with a size of 510 AU. Despite its compact and well condensed appearance,
neither clear CO outflow, radio jet, nor infrared sources (at a wave-length
shorter than 8 um) were detected at MMS 6-main even with the present
high-spatial resolution and high-sensitivity observations. The derived H_2
column density, 2.6x10^25 cm^-2, corresponds to a visual extinction of
A_v~15000 mag., and the derived number density is at least two orders of
magnitude higher than for the other OMC-2/3 continuum sources. The volume
density profile of the source was estimated to have a power-law index of 2 or
steeper down to a radius of ~450 AU. The time scale to form a protostar at the
center or the time scale elapsed after its formation is estimated to be 830 to
7600 yr. This is much shorter than the typical lifetime of the Class 0/I
protostars, which is ~10^(4-5) yr, suggesting that MMS 6-main is probably in
either the earliest stage of the proto-stellar core or in the latest stage of
the pre-stellar phase.

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The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
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The categories of this paper are: stat
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The categories of this paper are: cs
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ex
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The categories of this paper are: econ
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The categories of this paper are: comp-gas
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The categories of this paper are: physics
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The categories of this paper are: mtrl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-alg
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The categories of this paper are: cond-mat
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-ex