Enhanced star formation in the cometary globules of the GUM nebula

Abstract

Evidence for an enhanced rate of star formation in the cometary globules of the Gum nebula is presented. The IRAS Point Source Catalog has been searched for sources with spectral energy distributions characteristic of young stellar or protostellar objects associated with the compact heads of the cometary globules. The surface density of such sources associated with the cometary globule heads is found to be about 3-12 times the density in dark clouds in a neighboring comparison area and in the northern sky. The IRAS sources associated with the cometary globule heads have luminosities in the range from about 0.5 to about 20 solar luminosities, characteristic of low-mass young stellar or protostellar objects. It is suggested that the enhanced star formation in the cometary globule heads in the Gum nebula is a result of shock-induced star formation triggered by the same event that created the Gum nebula complex.