Chandra LETG Observations of Supernova Remnant 1987A

Abstract

We discuss the results from deep Chandra LETG observations of the supernova remnant 1987A (SNR 1987A). We find that a distribution of shocks, spanning the same range of velocities (from ~300 to 1700 km s-1) as deduced in the first part of our analysis, can account for the entire X-ray spectrum of this object. The postshock temperature distribution is bimodal, peaking at kT~0.5 and ~3 keV. Abundances inferred from the X-ray spectrum have values similar to those for the inner circumstellar ring, except that the abundances of nitrogen and oxygen are approximately a factor of 2 lower than those inferred from the optical/UV spectrum. The velocity of the X-ray-emitting plasma has decreased since 1999, apparently because the blast wave has entered the main body of the inner circumstellar ring.