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J. S. Kim, F. M. Walter (SUNY at Stony Brook), S. J. Wolk (CfA)
High mass stars can terminate low mass star formation (LMSF). However the strong UV radiation, winds, and shocks can also trigger LMSF by collapsing the denser cores of evaporating molecular clouds. The Gum Nebula is an excellent site to study how high mass stars may terminate and/or trigger LMSF. The nebula contains supernova remnants, \zeta Pup (O4If), \gamma2 Vel (WC8+O9), OB associations, and a large number of cometary globules (CGs) - bright rimmed evaporating dense cores of molecular clouds with cometary geometry. CGs are often associated with low mass pre-main sequence (PMS) stars in HII regions.
Here we present a multi-wavelength photometric study of selected regions around CG30/31/38 complex and RCW33 in the Gum Nebula. We present color-magnitude and color-color diagrams, and identify a locus of likely PMS stars. We will show the spatial distribution of PMS stars in these regions. RCW33 abuts the OB association Tr 10, which may have influenced its LMSF. The X-ray sources around CG30/31/38 outline the heads of the CGs which are pointing toward central ionizing sources. This region has probably been influenced by a runaway supergiant O star \zeta Pup. If these PMS stars around the CGs were formed in a evaporating molecular cloud, and have been since dispersed from their common birth place with typical 1-2km/sec velocity dispersion of PMS stars, their ages range from <0.5Myr to ~ 1-2Myr. There is evidence of on-going star formation, such as H-H objects, in both of the fields. We discuss the role these data may play in elucidating the history of triggered LMSF in the Gum Nebula.
The author(s) of this abstract have provided an email address for comments about the abstract: serena@mail.ess.sunysb.edu