Doikov, D. N.Andrievsky, Serhii M.Андрієвський, Сергій МихайловичАндриевский, Сергей Михайлович2017-12-212017-12-212017Odessa Astronomical publications = Одесские астрономические публикации = Одеські астрономічні публікаціїhttps://dspace.onu.edu.ua/handle/123456789/12240The light emission (“glow”) of cold dusty plasma of the remnant of SN1987A was confirmed by the Hubble Space Telescope observations on 7th January, 1995. In particular, Ca I and Ca II lines were recorded and identified in the spectrum of the supernova’s envelope. The period of complete hydrogen recombination in the remnant is 800 days. Thus, it is only radioactive decay that could be a primary source of the plasma light emission at the moment of observation. This paper describes the conditions of shock excitation and recombination of 44/20 Ca resulted from the decay of radioactive 44/20 Ti travelling in the remnant’s cold dust. The overionisation in the remnant resulted from the motion of the 44/20 Ca recoil nucleus, as well as its impact on the spectrum formation, was studied. It has been shown that the calcium lines are formed by the 44/20 Ca II ion in the inner layers of the remnant. We have reached the conclusion that the Ca I/Ca II lines strength ratio corresponds to the isotopic abundance ratio [44/20 Ca] /[44/20 Ca ] in type II supernova remnants.enSN1987A remnantradioactive elementsspectroscopy of Ca I and Ca IIArticle