Observed and Physical Properties of Core‐Collapse Supernovae

I use photometry and spectroscopy data for 24 Type II plateau supernovae toexamine their observed and physical properties. This dataset shows that theseobjects encompass a wide range of ~5 mag in their plateau luminosities, theirexpansion velocities vary by x5, and the nickel masses produced in theseexplosions go from 0.0016 to 0.26 Mo. From a subset of 16 objects I find thatthe explosion energies vary between 0.6x and 5.5x10^51 ergs, the ejected massesencompass the range 14-56 Mo, and the progenitors' radii go from 80 to 600 Ro.Despite this great diversity several regularities emerge, which reveal thatthere is a continuum in the properties of these objects from the faint,low-energy, nickel-poor SNe 1997D and 1999br, to the bright, high-energy,nickel-rich SN 1992am. This study provides evidence that more massiveprogenitors produce more energetic explosions, thus suggesting that the outcomeof the core collapse is somewhat determined by the envelope mass. I find alsothat supernovae with greater energies produce more nickel. Similarrelationships appear to hold for Type Ib/c supernovae, which suggests that bothType II and Type Ib/c supernovae share the same core physics. When the wholesample of core collapse objects is considered, there is a continousdistribution of energies below 8x10^51 ergs. Far above in energy scale andnickel production lies the extreme hypernova 1998bw, the only supernova firmlyassociated to a GRB.Comment: 25 pages, 7 figures, accepted for Part 1 of Astrophysical Journa