Supernova 1987A: The envelope mass and the explosion energy

Our study of the photometric and spectroscopic observations of SN 1987A based on the hydrodynamic modeling of its bolometric light curve and nonstationary hydrogen kinetics and energy balance when modeling the hydrogen spectral lines at the photospheric stage has shown that good agreement with the observations can be achieved only at a ratio of the explosion energy to the ejected-envelope mass of approximate to 0.83 x 10(50) erg M circle dot(-1). In this case, the radius of the presupernova is 35.0 +/- 5R(circle dot), and the surface chemical composition is typical of the LMC with the mass fractions of hydrogen X = 0.743, helium Y = 0.251, and heavy elements Z = 0.006. The analyzed dependence of the bolometric light curve on the mass of the ejected envelope at the above ratio of the explosion energy to the envelope mass suggests that the optimal mass is 18.0M((c)) with an admissible spread of +/- 1.5M(circle dot), and, accordingly, the explosion energy of SN 1987A is (1.50 +/- 0.12) x 10(51) erg. If a neutron star with a mass of approximate to 1.6M(circle dot) was formed through the gravitational collapse of an iron stellar core, then the mass of the presupernova immediately before the explosion of SN 1987A was 19.6 +/- 1.5M(circle dot). (c) 2005 Pleiades Publishing, Inc.