Astronomy and Astrophysics – Astrophysics
Scientific paper
Jul 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994a%26a...287..947k&link_type=abstract
Astronomy and Astrophysics 287, 947-958 (1994)
Astronomy and Astrophysics
Astrophysics
31
Stars: Formation, Ism: Dust, Ism: Molecules, Ism: Clouds, Ism: Hh24 Mms, Radio Lines: Ism
Scientific paper
We present CO and CS data of the recently discovered protostar candidate HH24 MMS in the Orion region for which submm/mm continuum observations of the dust yielded an angular size of =~15", a temperature of about 10K and gave evidence for gravitational instability. The new molecular line data indicate that the source is a cold spot in an extended molecular cloud because the CO line temperature is higher than the color temperature of the dust. In contrast to its appearance in the dust continuum, the source is not prominent in C^18^O nor in CS suggesting that the molecules are partially frozen out. There is no indication of a strong outflow in CO. Mass estimates from C^18^O are roughly a hundred times lower than from the mm/submm dust emission. The large discrepancy is probably a combined effect of molecular underabundance and an enhanced absorption coefficient of the dust at 1mm. Furthermore, we calculate theoretical profiles of CO and CS for a cloud core like HH24 MMS in order to identify observable spectral signatures for collapse. We find that the most promising clue will come from CS lines observed with a resolution that is a factor 3 higher than the present data. Such transitions are expected to show an absorption feature that shifts to progressively larger velocities with increasing j-number. The present observations of C^18^O and CS are in accord with this model.
Chini Rolf
Kruegel Endrick
No associations
LandOfFree
Analysis of a cold cloud fragment does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Analysis of a cold cloud fragment, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Analysis of a cold cloud fragment will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1252261