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   52003
   X-ray emission from protostars has recently been detected by both ROSAT
   and ASCA. Although such emission is common from the slightly older T
   Tauri star class (interpreted as enhanced solar type magnetic
   activity), emission from the much younger and cooler protostellar phase
   is not well understood. We seek to better understand the nature of this
   emission which has important implications for star formation regulation
   and the ionization of circumstellar disks and outflows. Three fields
   are proposed containing the near-by, well-separated, luminous
   protostars, L723, RNO 43 and RNO 91. ASCA's unique ability to observe
   protostars through heavy extinction is necessary for this project.
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