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   71021
   We propose to observe Bok globules which contain Class 0 protostar in
   it. Bok globule is the most compact and isolated molecular cloud and
   then would have less absorption for the young age. Our goal is to
   detect Class 0 protostar at the first time, and to investigate; (1)
   when a star begins to emit X-rays, (2) what is the difference in X-rays
   (spectrum and time variability) between Class 0 and Class I, and the
   other phases of star formation (ClassII, III), and (3) what is the X-
   ray emission mechanism in the protostar phase.
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