Protostars and Planets VI, Heidelberg, July 15-20, 2013
Poster 1S035
CO study of the cometary globule CG 1
Haikala, Lauri K. (FINCA, University of Turku and Department of Physics, University of Helsinki, Finland)
Mäkelä, Minja M. ( Department of Physics, University of Helsinki, Finland)
Abstract:
Cometary globule CG 1 is a ´´classic´´ cometary globule in the Gum
nebula. We study the structure and mass distribution of CG1 and star
formation in it using NTT SOFI J,H,Ks NIR photometry and SEST CO J=2-1
and J=1-0 molecular line observations. We aim to find clues to the
cometary globule formation mechanism: radiation driven implosion (RDI)
or a supernova blast. In RDI models major part of the CG mass is
concentrated in the globule head whereas in the supernova blast models
large part of the mass can lie in the tail. Gum nebula is a HII
region and a possible supernova remnant and either RDI or supernova
blast or both mechanisms are possible. So far four stars have been
formed in CG1. CO emission from the cloud is strong but the
intensity/velocity structure is complicated partly because of outflow
activity from the protostar embedded in the globule head. The
complicated velocity/excitation structure in the cloud prevents
accurate mass estimation from CO emission. The approximate 13CO
masses of the emission maxima in the globule head and tail are 13 Msun and
23 Msun, respectively. These are similar to those derived from SOFI
NIR photometry, 17 Msun and 32 Msun. We conclude however that star
formation has modified the pre-star formation structure of the globule
and no firm conclusion on the CG formation mechanism can be drawn from
the present observed mass distribution.
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