J/A+A/481/93 CO and HC3N maps of IRAS 20050+2720 (Beltran+, 2008)
On the nature of outflows in intermediate-mass protostars:
a case study of IRAS 20050+2720.
Beltran M.T., Estalella R., Girart, J.M., Ho P.T.P, Anglada G.
<Astron. Astrophys. 481, 93 (2008)>
=2008A&A...481...93B 2008A&A...481...93B
ADC_Keywords: Interstellar medium ; Interferometry ; Protostars
Keywords: ISM: individual objects: IRAS 20050+2720 - ISM: jets and outflows -
stars: circumstellar mass - stars: formation
Abstract:
This is the third in a series of papers devoted to studying
intermediate- mass molecular outflows and their powering sources in
detail and with high -angular resolution. This paper studies the
intermediate-mass YSO IRAS 20050+2720 and its molecular outflow and
puts the results of this and the previous studied sources in the
context of intermediate-mass star formation. We carried out VLA
observations of the 7mm continuum emission and OVRO observations of
the 2.7mm continuum emission, CO (1-0), C18O (1-0) and HC3N (12-11) to
map the core towards IRAS 20050+2720. The high-angular resolution of
the observations allowed us to derive the properties of the dust
emission, the molecular outflow, and the dense protostellar envelope.
By adding this source to the sample of intermediate-mass protostars
with outflows, we compared their properties and evolution with those
of lower mass counterparts. The 2.7mm continuum emission has been
resolved into three sources, labeled OVRO 1, OVRO 2, and OVRO 3. Two
of them, OVRO 1 and OVRO 2, have also been detected at 7mm. OVRO 3,
which is located close to the C18O emission peak, could be associated
with IRAs 20050+2720. The mass of the sources, estimated from the dust
continuum emission, is 6.5M☉ for OVRO 1, 1.8M☉ for OVRO 2,
and 1.3M☉ for OVRO 3. The CO (1-0) emission traces two bipolar
outflows within the OVRO field of view, a roughly east-west bipolar
outflow, labeled A, driven by the intermediate-mass source OVRO 1, and
a northeast-southwest bipolar outflow, labeled B, probably powered by
a YSO engulfed in the circumstellar envelope surrounding OVRO 1. The
multiplicity of sources observed towards IRAS 20050+2720 appears to be
typical of intermediate-mass protostars, which form in dense clustered
environments. In some cases, as for example IRAS 20050+2720,
intermediate- mass protostars would start forming after a first
generation of low-mass stars has completed their main accretion phase.
The properties of intermediate-mass protostars and their outflows are
not significantly different from those of low-mass stars. Although
intermediate-mass outflows are intrinsically more energetic than those
driven by low-mass YSOs, they do not show intrinsically more complex
morphologies when observed at high angular resolution. Known
intermediate-mass protostars do not form a homogeneous group. Some
objects are likely in an earlier evolutionary stage as suggested by
the infrared emission and the outflow properties.
Description:
The files are the OVRO data used to produce the map in Fig. 1 and the
OVRO data cubes used to produce the maps in Fig. 2, 3 and 6 of the
paper. Units are Jy/beam. Coordinate system is equatorial (J2000.0).
Objects:
------------------------------------------------------------
RA (2000) DE Designation(s)
------------------------------------------------------------
20 07 05.80 +27 28 58.1 IRAS 20050+2720 = IRAS 20050+2720
------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
maps.dat 40 4 Images list
fit/* . 4 FITS files
--------------------------------------------------------------------------------
See also:
J/A+A/432/921 : Massive protostellar candidates (Fontani+, 2005)
J/A+A/447/221 : Dust continuum emission from IRAS sources (Beltran+, 2006)
J/A+A/474/911 : 1.3mm and CO(2-1) maps of IRAS 20343+4129 (Palau+, 2007)
Byte-by-byte Description of file: maps.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- FileName Name of the fit file in subdirectory fit
17- 40 A24 --- Title Title of the file
--------------------------------------------------------------------------------
Acknowledgements:
Maria T. Beltran, mbeltran(at)am.ub.es
(End) Maria T. Beltran [U. Barcelona, Spain], Patricia Vannier [CDS] 29-Feb-2008