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B.E. Sugerman, S.S. Lawrence, A.P.S. Crotts (Columbia University)
The development of SNR 1987A provides an unprecedented opportunity to observe, at high spatial, spectral and temporal resolution, the birth of a supernova remnant. As the interaction (hot spots) between the SN ejecta and the circumstellar equatorial ring (ER) intensifies, this region will undergo radical changes, leaving increasingly less pristine ER with which to reconstruct the mass-loss history of the progenitor and the ring formation mechanism. As such, a more complete understanding of the nebular structure and interaction regions are crucial.
We report results from continued study of the ER using new and archival HST WFPC2 and STIS imaging. We measure the physical properties of the ER in nebular lines and compare to WFPC & FOC results. Spatially-resolved light-curves of the ER indicate that the ER does not evolve monolithically. On large-scales, the northern (near) limb is brighter, and fading more rapidly, than the southern (far) side. Small-scale differences in the ER flux yield additional clues to the density structure of the emitting gas. We discuss this data within the context of current ER emission models. We present multi-wavelength lightcurves of the first hot spot, and using PSF-matched difference-imaging analysis of the hot spots in STIS F28x50LP imaging, constrain short-term variability. This data is critical to modeling the density, temperature, composition and formation mechanism of the ER.
This research was supported by NASA grant NAG5-3502 and STScI grants GO 8806 and GO 8872.