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   PR # 42084
   We propose to use ASCA to study the evolution of the CTB1 supernova
   remnant. The existing ROSAT PSPC data are insufficient, and we are
   concerned that the conventional Sedov-phase interpretation is
   incomplete. In particular, the optical and radio data suggest that
   the blast wave may recently have encountered a cavity wall, and the
   X-ray images show a center-filled morphology with a possible
   break-out region to the northeast. We will fit the ASCA data with
   predictions from our dusty shock wave code to determine physical
   parameters from the western and northeastern regions of the remnant.
   These will be used to determine the evolutionary epoch of CTB1.
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