Hubble Space Telescope Observations of the Shocks in Supernova Remnant SN 1987A

Abstract

We present observations of supernova remnant SN 1987A made with the Hubble Space Telescope. The bright spot previously observed on the inner circumstellar ring by the Wide Field/Planetary Camera at a position angle ~31^deg has brightened by nearly a factor of 2 in seven months. Space Telescope Imaging Spectrograph (STIS) spectra confirm that this spot is the result of a ~300 km s^-1 shock entering the inner circumstellar ring at the first point of contact by the supernova blast wave. High-velocity (~15,000 km s^-1) Lyα and Hα emission are apparent in the STIS spectra as well. This emission comes in part from neutral hydrogen in the debris crossing a reverse shock located at ~75% of the radius of the inner boundary of the inner circumsteller ring and confined within +/-30^deg of the equatorial plane.