COOLING BALANCE AND THERMAL-INSTABILITY OF A COLLAPSING MOLECULAR PROTOCLOUD

Authors
Citation
D. Puy et M. Signore, COOLING BALANCE AND THERMAL-INSTABILITY OF A COLLAPSING MOLECULAR PROTOCLOUD, New astronomy, 3(4), 1998, pp. 247-257
Citations number
35
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
13841092
Volume
3
Issue
4
Year of publication
1998
Pages
247 - 257
Database
ISI
SICI code
1384-1092(1998)3:4<247:CBATOA>2.0.ZU;2-5
Abstract
Molecular line emissions play an important role in the thermal balance of collapsing molecular clouds. In the present paper we calculate ana lytically the molecular cooling due to H-2 and HD, the last being the main cooling agent around 200 K (Puy & Signore, 1997 [NewA, 2, 299]). Our analysis is done under the hypothesis: we consider only the first two excited levels of the H-2 and HD molecules. We analyse the ratio b etween the molecular cooling due to HD and that due to H-2. The potent iality of fragmentation of these collapsing protoclouds through the th ermal instability is also discussed. Finally, we suggest that this stu dy could also be extended to the CO molecule, because the carbon reser voir molecule CO has already been observed in high redshift objects. ( C) 1998 Elsevier Science B.V.