Issue |
A&A
Volume 454, Number 2, August I 2006
APEX Special Booklet
|
|
---|---|---|
Page(s) | L71 - L74 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361:20065387 | |
Published online | 11 July 2006 |
Letter to the Editor
C
O (3–2) observations of the Cometary Globule CG 12: a cold core and a C
O hot spot
1
Observatory, PO Box 14, University of Helsinki, Finland e-mail: haikala@astro.helsinki.fi
2
European Southern Observatory, Casilla 19001, Santiago, Chile
Received:
7
April
2006
Accepted:
3
June
2006
The feasibility of observing the (3–2) spectral
line in cold clouds with the APEX telescope has been tested. As the
line at 329.330 GHz lies in the wing of a strong atmospheric H2O
absorption it can be observed only at high altitude observatories.
Using the three lowest rotational levels instead of only two helps to
narrow down the physical properties of dark clouds and globules. The
centres of two
maxima in the high latitude low mass star forming
region CG 12 were mapped in
(3–2) and the data were analyzed
together with spectral line data from the SEST. The
TMB (3–2)/TMB (2–1) ratio in the northern
maximum, CG 12-N, is 0.8, and in the southern maximum, CG 12-S, ~2. CG 12-N is modelled
as a 120´´ diameter (0.4 pc) cold core with a mass of 27
. A small size maximum with a narrow, 0.8
,
(3–2)
spectral line with a peak temperature of TMB K was detected
in CG 12-S. This maximum is modelled as a 60´´-80´´
diameter (~0.2 pc) hot (Tex K)
~1.6
clump. The source lies on the axis of a highly
collimated bipolar molecular outflow near its driving source. This is
the first detection of such a compact, warm object in a low mass star
forming region.
Key words: clouds / ISM molecules / ISM: structure / radio lines / ISM: individual objects: CG 12, NGC 5367
© ESO, 2006
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