I am working with Lynne Hillenbrand, using the Galaxy Evolution Explorer to efficiently identify nearby stars less than 100 million years old. The currently known populations of young stellar associations are only a few million years old, even though star formation might be expected to last for 10 million years or more. This so-called "Post-T-Tauri star problem" is unresolved in part because many methods for identifying young stars are strongly biased against stars more than 1-2 million years old. We do not know whether the apparent absence of 10 million year old stars is real or merely a selection effect.
Since young stars show strong chromospheric activity, which produces ultraviolet emission, until they are well over 100 million years old, a search with GALEX for stars with an ultraviolet excess should reveal post-T-Tauri stars if they exist. We have used GALEX observations toward the nearby Taurus and Upper Scorpius star forming regions to search for ultraviolet-excess stars. We have found several candidates, as well as an unexpectedly large background of ultraviolet-excess stars that are unassociated with the star forming regions. We are now carrying out several follow-up programs to confirm and characterize our young star candidates.
"Ultraviolet Excess Stars Towards Taurus and Upper Scorpius", Findeisen, K.; Hillenbrand, L. 2010, submitted to AJ
"An Ultraviolet-Selected Sample of Young Stars", Findeisen, K.; Hillenbrand, L. 2009, in American Astronomical Society Meeting 213, #414.08 ADS