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)

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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