Issue |
A&A
Volume 424, Number 1, September II 2004
|
|
---|---|---|
Page(s) | 179 - 195 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20035848 | |
Published online | 17 August 2004 |
Nature of two massive protostellar candidates: IRAS 21307+5049 and IRAS 22172+5549
1
Dipartimento di Astronomia e Fisica dello spazio, Largo E. Fermi 2, 50125 Firenze, Italy e-mail: fontani@arcetri.astro.it
2
INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
3
IFSI, CNR, Via Fosso del Cavaliere, 00133 Roma, Italy
4
Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
5
Istituto di Radioastronomia, CNR, via Gobetti 101, 40129 Bologna, Italy
Received:
11
December
2003
Accepted:
1
June
2004
We present observations of continuum and molecular lines towards the
protostar candidates IRAS 21307+5049 and IRAS 22172+5549.
Single-dish
maps in the 12CO (2–1), C18O (2–1), H13CO+ (1–0) lines and 850 μm
continuum are compared with interferometric maps in the 12CO (1–0) line and
3 mm continuum, and with mid- and near-infrared images. Also, single-pointing
spectra of the CH3C2H (6–5), (8–7) and (13–12) lines observed towards
IRAS 21307+5049, and H2 and [FeII] line emission observed towards
IRAS 22172+5549, are presented. A plausible interpretation of our data
based on the continuum maps and spectral energy distributions is that
two components are present: a compact molecular core, responsible for the
continuum emission
at wavelengths longer than ~m, and a cluster of stars
located close to the center of the core, but not spatially coincident
with it, responsible for the emission at shorter wavelengths.
The core is approximately located at the center of the
associated molecular outflow, detected for both sources in the 12CO (1–0) and
(2–1) lines. The cores have masses of ~
,
and luminosities of ~
. The outflows parameters
are consistent with those typically found in high-mass
young stellar objects.
Our results support the hypothesis that in these sources the luminosity
is dominated by accretion rather than by nuclear burning.
We conclude that the sources embedded inside the cores are likely
protostars with mass ~
.
Key words: stars: formation / radio lines: ISM / ISM: molecules
© ESO, 2004
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