The structure of the circumstellar gas of SN 1987A

Abstract

Recent observations of the rings around SN 1987A are discussed and modeled, with particular emphasis on HST observations of the inner ring by the SINS team (P.I.: R. P. Kirshner). It is found that the lowest density detected in the ring is roughly (1-2)E3 cm-3. The geometry of the inner ring is constrained by its different size in [N II] and [O III]. The implications of this on the distance to the supernova are discussed and we find an upper limit of 54.2 +/- 2.2 kpc, which is in agreement with recent RR Lyrae and Cepheid measurements. In addition, preliminary results are presented for improved calculations of the supernova breakout.