AAS 203rd Meeting, January 2004
Session 33 Young Stars
Oral, Monday, January 5, 2004, 2:00-3:30pm, Regency VII

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[33.04] Searching for Nearby, Post T-Tauri Stars

I. Song, B. Zuckerman (UCLA), M.S. Bessell (Australian National University)

By examination of the all-sky ROSAT, Hipparcos, Tycho-2 and SuperCOSMOS catalogs, we have selected a set of ~3000 stars that should include the youngest (\lesssim100\,Myrs), closest (\lesssim60\,pc) stars to Earth. During the past three years, we have observed ~1000 targets from the Siding Spring Observatory in New South Wales, Australia and Lick Observatory of the University of California. About 20\,% of the observed stars, with spectral type between A and M, turn out to be young and close to Earth. Some of the newly identified young stars are members of already known stellar groups (TW Hydrae Association, beta Pic moving group, and Tucana/Horologium Association) while a majority are apparently young field stars not belonging to any known stellar group.

These stars are excellent targets for planet formation/evolution studies because of their proximity to Earth and age range (5-30 Myr). This age range corresponds to the critical stage of planet formation in our Solar System; gas giant planet formation in \lesssim10\,Myr and terrestrial planet formation in \lesssim30\,Myr. These stars are excellent targets for direct imaging detection of cooling planets because young giant planets are hot (hence bright at near infrared wavelengths) in youth. Any planets (and/or planetary disks) to be found will provide crucial information on formation and early evolution of planetary systems.

This research was supported in part by the UCLA Astrobiology Institute and by NASA grants to UCLA.

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.