• IPAC



Star Formation in CG4: Using infrared and optical space and ground based images to search for newly forming stars in Cometary Globule 4.


We propose to look for new young stellar objects (YSOs) in Cometary Globule 4 (CG4) in Puppis. We will attempt to answer the following questions:

  • Will (additional) stars form here?
  • What triggers star formation?
  • Has a cluster formed?

CG4 is approximately 1300 parsecs/4680 LY away. It is one of about 30 cometary globules in the Gum Nebula (Choudhury and Bhatt 2008), many of which are known to be forming stars. These globules are pointed generally radially outward from the center of the Vela OB2 association, which is also forming stars. CG4 is dramatic in appearance, and that has brought it to the attention of both scientists and the public. Recent visible and visible/infrared mosaics have been featured in Astronomy Magazine and Science News Magazine.

Our team will use archival Spitzer InfraRed Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS) data, 2 Micron All Sky Survey (2MASS) data, and XMM-Newton/ESA x-ray spectroscopy data from that space telescope, as well as optical data obtained by collaborators. We expect to recover the previously known YSOs (Reipurth and Pettersson 1993) and find additional new YSOs in this region. We will primarily use infrared excess to find new YSOs.

There may be some non-member CG4 objects in this candidate group; so, along with CG4's YSOs, we may find extragalactic sources (i.e., active galactic nuclei, etc.) and other stars from our Galaxy. We will use all available data to attempt to determine legitimate cluster members, and to separate CG4's YSOs from other objects with similar spectral energy distributions (SEDs).

Participant Educator


Ms. Vivian Hoette

Yerkes Observatory, University of Chicago, Williams Bay, Wisconsin

Participant Educator


Ms. Carolyn Mallory

Pierce College, Woodland Hills, California

Participant Educator


Mr. Kevin McCarron

Oak Park and River Forest High School, Oak Park, Illinois



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