Title:
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The Structure of the Circumstellar Gas of SN 1987A

Authors:
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Peter Lundqvist (Stockholm Observatory) & George Sonneborn (Goddard)

Abstract:
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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)E^3 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.

To appear in:
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``SN 1987A: Ten Years After, The Fifth CTIO/ESO/LCO Workshop''
(eds. M. Phillips & N. Suntzeff)