A Spitzer view of protoplanetary disks in the γ Velorum cluster

Creators: Hernandez, Jesús; Hartmann, Lee; Calvet, Nuria; Jeffries, R. D.; Gutermuth, R.; Muzerolle, J.; Stauffer, J.

Abstract

We present new Spitzer Space Telescope observations of stars in the young (~5 Myr)γ Velorum stellar cluster. Combining optical and 2MASS photometry, we have selected 579 stars as candidate members of the cluster. With the addition of the Spitzer mid-infrared data, we have identified five debris disks around A-type stars and five to six debris disks around solar-type stars, indicating that the strong radiation field in the cluster does not completely suppress the production of planetesimals in the disks of cluster members. However, we find some evidence that the frequency of circumstellar primordial disks is lower, and the infrared flux excesses are smaller than for disks around stellar populations with similar ages. This could be evidence for a relatively fast dissipation of circumstellar dust by the strong radiation field from the highest mass star(s) in the cluster. Another possibility is that γ Velorum stellar cluster is slightly older than reported ages and the low frequency of primordial disks reflects the fast disk dissipation observed at ~5 Myr.

Additional Information

© 2008 The American Astronomical Society. Print publication: Issue 2 (2008 October 20). Received 2008 March 3, accepted for publication 2008 June 16. We thank Aletta Tibbetts for helping us in the initial steps of the IRAC reduction data. An anonymous referee provided many insightful comments. This publication makes use of data products from Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, California Institute of Technology. This work is based on observations made with the Spitzer Space Telescope (GO-1 0037), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. Support for this work was provided by University of Michigan and NASA grants NAG5-13210, NASA-1277575, and NASA-1285169.

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