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   81201
   We propose long look observations of V773 Tau. V773 Tau is a very
   active T Tauri star which frequently exhibits large X-ray flares. We
   investigate (1) a flare duty ratio, (2) heating and cooling processes
   of the flaring plasma, (3) a structure of a circumstellar disk using
   the absorption column density during flares, and (4) the low metal
   abundance problem observed in young stars. The observations will lead
   to our understanding of X-ray flares from T Tauri stars.
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