Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hot Molecular Cores and the Formation of Massive Stars   It has been proposed that some hot molecular cores (HMCs) harbor a young
embedded massive star, which heats an infalling envelope and accretes mass at a
rate high enough to ``choke off'' an incipient HII region. This class of HMCs
would mark the youngest phase known of massive star formation. In order to test
this hypothesis, we model this type of object calculating the radiative
transfer through a spherically symmetric dusty envelope infalling onto a
central OB star, with accretion rates from 0.0006 to 0.001 solar masses per
year. The dust thermal spectrum from infrared to radio wavelengths is derived
and is compared with the observed fluxes of several hot cores which may be
internally heated. We find that the data are best fitted using an envelope with
the density distribution resulting from the collapse of a singular logatropic
sphere, instead of that of a singular isothermal sphere. We conclude that
several of these sources may be undergoing an intense accretion phase and find
in all the cases that the accretion luminosity exceeds the stellar luminosity.
We discuss the implications of this phase on the formation of massive stars.

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The categories of this paper are: atom-ph
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The categories of this paper are: ao-sci
18
The categories of this paper are: econ
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: chao-dyn
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The categories of this paper are: chem-ph
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The categories of this paper are: q-bio
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The categories of this paper are: stat
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The categories of this paper are: patt-sol
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The categories of this paper are: acc-phys
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The categories of this paper are: adap-org
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The categories of this paper are: nlin
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-th