Supernova 2008D: A Repetition of Supernova 1987A In a Binary

TL;DR

This paper analyzes Supernova 2008D, comparing it to SN 1987A, and suggests it resulted from a lower-mass progenitor with a black hole remnant, providing insights into supernova mechanisms and remnant masses.

Contribution

It offers a revised analysis of SN2008D's light curve and remnant mass, highlighting differences from SN1987A and proposing a lower-mass progenitor and black hole remnant.

Findings

SN2008D's remnant likely less massive than SN1987A's

Maximum neutron star mass estimated at 1.5 solar masses

SN2008D's progenitor had a lower initial mass than 18 M_sun

Abstract

The Supernova 2008D is similar to that of SN 1987A without the H-envelope. Soderberg et al.(2008) reported the serendipitous discovery of the SN2008D at the time of the explosion, accompanied by an X-ray outburst XRF080109. The central remnant, which we believe to be the black-hole (BH) central engine in the Blandford-Znajek mechanism, is estimated, on the basis of the 7% 56Ni production, to have a mass of 1.6-1.8 M_sun. This is not much larger than the upper limit of 1.56 m_sun for the mass of the compact object in SN1987A found by Bethe & Brown (1995); also, on the basis of the 7.5% 56Ni production, they interpreted it as a low-mass BH. Redoing the light curve so as to take into account the absence of convective carbon burning from zero age main sequence 18-24 M_sun and replacing it by carbon shell burning, we see that the remnant in SN2008D must be less massive than in SN 1987A; there of 18 M_sun. Thus, the maximum neutron star mass is 1.5 M_sun. Note that the metallicity of the host galaxy of SN2008D is similar to that of our Galaxy.