Ionisation loss and shock excitation of 44/20 Са I and 44/20 Са II atoms in cold remnants of type II supernovae
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Дата
2017
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Одеський національний університет імені І. І. Мечникова
Анотація
The 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.
Опис
Ключові слова
SN1987A remnant, radioactive elements, spectroscopy of Ca I and Ca II
Бібліографічний опис
Odessa Astronomical publications = Одесские астрономические публикации = Одеські астрономічні публікації