Star formation studies with the sloan digital sky survey

The determination of time scales associated with planetary formation and circumstellar disk evolution requires large samples of stars having diverse environments and ages. Such a sample can be obtained using the Sloan Digital Sky Survey (York et al. 2000), as it is systematically mapping one-quarter of the entire sky providing photometric data on over 100 million objects in five passbands (Gunn et al. 1998; Fukugita et al. 1996). Pre-main sequence stars have distinct colors in the SDSS u'g'r'i'z' photometric system as a consequence of their late-type photospheres and strong UV excess driven by the magnetospheric accretion shock. SDSS observations of known Orion population emission line stars cataloged by the Kiso objective prism survey reveal a color-based signature that correlates well with the Ha emission line strength. As the excess emission is a direct consequence of the presence of a circumstellar disk, we can constrain the duration of the planetary formation process by determining the age of the young star. Follow-on observations of SDSS T Tauri candidates have begun at the Astrophysical Research Consortium's 3.5 meter telescope using medium resolution (R = 5000) spectroscopy. The aim is to place these objects on theoretical evolutionary tracks using spectral indicators for effective temperature and surface gravity and to create a catalog for future studies including a circumstellar disk census.