DETECTION OF SHOCKED MOLECULAR-HYDROGEN IN INFRARED COMPANIONS TO T-TAURI STARS - EVIDENCE FOR ONGOING ACCRETION

We report the detection of the 2.12 mu m, upsilon = 1-0 S(1) emission line of molecular hydrogen spatially confined to the infrared companions of the Hare 6-10 and UY Aur binary systems. The primaries in both sources appear to be relatively normal pre-main-sequence stars. The K-band spectrum of the Hare 6-10 companion is unusually red and displays no characteristic stellar features. The UY Aur infrared companion, on the other hand, is undoubtedly a star. Our nondetection of the upsilon = 2-1 S(1) line of H-2 implies line ratios inconsistent with a fluorescent origin for the emission and suggests that it is produced by shock heating. These observations strengthen the view that the infrared companions are experiencing ongoing accretion.