LIGHT-CURVE STUDIES OF SN 1993J AND SN 1994I

Numerical light curve calculations have been carried out to constrain the light-curve parameters of the recent SNs 1993J and 1994L. For SN 1 993J the radius of the progenitor star is constrained to be in the ran ge 2-4 x 10(13) cm which is consistent with the candidate progenitor s tar. The ejected mass is constrained to be in the range 1.9-3.5 M circ le dot; equating the ejected mass to the helium core mass of the proge nitor implies a main-sequence mass in the range 12-17 M circle dot. Us ing the new Cepheid distance to M81, the ejected Ni-56 mass is found t o be in the range 0.10-0.14 M circle dot, For SN 1994I the ejected mas s is in the range 0.9-1.3 M circle dot; equating the ejected mass to t he carbon-oxygen core mass of the progenitor implies a main-sequence m ass in the range 13-20 M circle dot. For a distance of 7 Mpc and an ex tinction A(V) = 1.4 mag, the ejected Ni-56 mass is found to be 0.07 M circle dot.. Recent studies of galactic chemical evolution have sugges ted that the main-sequence masses and ejected Ni-56 masses of core col lapse SNs may be inversely correlated. We examine this effect for 1993 J, 1994I, and 1987A, but the small number of known nickel mass-main-se quence mass systems makes it too early to draw definitive conclusions.