Intermediate Mass Young Stars Showing Peculiar X-ray Features

Recent ROSAT and ASCA observations have revealed that intermediate mass young stars are Xray emitters. We found that the Xray emission probably originates from the magnetic activity, which continues the early phase of the mainsequencestage for Btype stars. With the Chandra and ASCA observations, we found two young stars, rho Oph S1 and HR 6000, showed characteristic Xray features; low abundance thermal or nonthermal emission and rapid variation, but the detailed feature is uncertain due to the lack of photon statistics. With XMMNewton, we determine whether the Xray emission is thermal or not, and see the variation of Xray intensity in a short timescale. From these features, we reveal the Xray emission mechanism. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]