CCD SOFT-X-RAY OBSERVATIONS OF THE PUPPIS-A SUPERNOVA REMNANT

We present the first images and spectra of an astronomical object, oth er than the Sun, acquired with a CCD imaging X-ray spectrometer. Durin g a 230 s sounding rocket observation, we have acquired moderate-resol ution spectra and moderate-resolution images of a portion of the Pup A supernova remnant (SNR). Based on these data, we conclude that the X- ray spectrum of Pup A is inconsistent with any single-temperature equi librium or nonequilibrium plasma model. We find evidence for variation s in the emitting plasma on scales as small as 5'.0 and as large as 30 '.0. The spatial structure of the spectral variations in the remnant i s found to be inconsistent with the standard Sedov model for the evolu tion of a SRN into a homogeneous interstellar medium (ISM). We suggest that the remnant is expanding into a region of the ISM having a densi ty of approximately 1 cm-3 with inhomogeneities on the order of 50%. W e have found evidence for the presence of a knot of plasma enriched in neon, but require more data to be conclusive.