AAS 200th meeting, Albuquerque, NM, June 2002
Session 71. Stellar Youth: Tomorrow's Degenerates
Display, Thursday, June 6, 2002, 9:20am-4:00pm, SW Exhibit Hall

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[71.11] Pre-mainsequence candidates among F stars with uvby and 2MASS photometry

A. A. Suchkov (STScI)

Using uvby and 2MASS data, we have identified an extensive population of F stars that appear to be pre-mainsequence (PMS). Most of these stars are spatially associated with known regions of ongoing star formation, many exhibit near-infrared excess suggestive of the presence of hot circumstellar dust. Their distribution across the \log Te - MV diagram is consistent with expectations for PMS but not ZAMS or post-mainsequence stars, exhibiting a very large excess of hot, luminous stars. The PMS candidates are dominated by reddened stars. There is evidence that in many case much of the reddening occurs in the circumstellar dusty environment rather than in the interstellar medium. On the other hand, there are PMS candidates with no detectable reddening. Both reddened and unreddened candidates have a typical metallicity above solar, their fraction dropping dramatically at lower metallicity.

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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.