G305.136+0.068: A massive and dense cold core in an early stage of evolution
Author
dc.contributor.author
Garay Brignardello, Guido
Author
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Mardones Pérez, Diego
Author
dc.contributor.author
Contreras Morales, Yanett Alejandra
Author
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Pineda, Jaime
Author
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Servajean Bergoeing, Elise
Author
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Guzmán Fernández, Andrés
Admission date
dc.date.accessioned
2015-04-22T13:30:39Z
Available date
dc.date.available
2015-04-22T13:30:39Z
Publication date
dc.date.issued
2015-01-20
Cita de ítem
dc.identifier.citation
The Astrophysical Journal, 799:75 (8pp), 2015 January 20
en_US
Identifier
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doi:10.1088/0004-637X/799/1/75
Identifier
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https://repositorio.uchile.cl/handle/2250/130168
General note
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Artículo de publicación ISI
en_US
Abstract
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We report molecular line observations, made with ASTE and SEST, and dust continuum observations at 0.87 mm,
made with APEX, toward the cold dust core G305.136+0.068. The molecular observations show that the core is
isolated and roughly circularly symmetric and imply that it has a mass of 1.1 × 103 M. A simultaneous model
fitting of the spectra observed in four transitions of CS, using a non-LTE radiative transfer code, indicates that
the core is centrally condensed, with the density decreasing with radius as r−1.8, and that the turbulent velocity
increases toward the center. The dust observations also indicate that the core is highly centrally condensed and that
the average column density is 1.1 g cm−2, a value slightly above the theoretical threshold required for the formation
of high-mass stars. A fit to the spectral energy distribution of the emission from the core indicates a dust temperature
of 17 ± 2 K, confirming that the core is cold. Spitzer images show that the core is seen in silhouette from 3.6 to
24.0μm and that it is surrounded by an envelope of emission, presumably tracing an externally excited photodissociated
region. We found two embedded sources within a region of 20 centered at the peak of the core, one of
which is young, has a luminosity of 66L, and is accreting mass with a high accretion rate of ∼1 × 10−4 M yr−1.
We suggest that this object corresponds to the seed of a high-mass protostar still in the process of formation. The
present observations support the hypothesis that G305.136+0.068 is a massive and dense cold core in an early stage
of evolution, in which the formation of a high-mass star has just started.