  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.
