<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mastichiadis, A.</style></author><author><style face="normal" font="default" size="100%">Kylafis, N.</style></author><author><style face="normal" font="default" size="100%">Ventura, J.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Supernova 1987A : envelope metallicity and the nature of the soft X-ray component.</style></title><short-title><style face="normal" font="default" size="100%">Astronomy and Astrophysics</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Astrophysics</style></keyword><keyword><style  face="normal" font="default" size="100%">Cobalt Isotopes</style></keyword><keyword><style  face="normal" font="default" size="100%">Metallicity</style></keyword><keyword><style  face="normal" font="default" size="100%">Monte Carlo method</style></keyword><keyword><style  face="normal" font="default" size="100%">Neutron stars</style></keyword><keyword><style  face="normal" font="default" size="100%">Stellar Envelopes</style></keyword><keyword><style  face="normal" font="default" size="100%">Supernova 1987a</style></keyword><keyword><style  face="normal" font="default" size="100%">X Ray Sources</style></keyword><keyword><style  face="normal" font="default" size="100%">X Ray Spectra</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1989</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1989/01/1</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://ui.adsabs.harvard.edu/abs/1989A&amp;A...208L..11M</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">208</style></volume><pages><style face="normal" font="default" size="100%">L11 - L14</style></pages><isbn><style face="normal" font="default" size="100%">0004-6361</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The observed X-ray spectra reported by the GINGA and MIR-HEXE satellite experiments contain information on the metallicity of the Supernova's expanding envelope. Using a Monte Carlo code to simulate the Compton degradation of the ^56^Co -produced γ-rays, we calculate the emerging X-ray spectrum for various metallicities. The observed spectra are compatible with a low (less than solar) metal abundance, while an additional soft component, independent of the ^56^Co source is probably required in order to account for the data. The evolution of the spectral hardness is used as a sensitive indicator of the nature of the soft component, and of the possible contribution of an imbedded pulsar to the X-ray spectrum.</style></abstract></record></records></xml>