A Type II supernova's bolometric tail luminosity is measured to be at days after explosion

PHYSICS · Subjective · Fermi University Physics · Nuclear Physics · Astrophysics & Cosmology · Radioactivity and decay modes

Stars from the Inside, Ch Stellar explosions: core collapse, the neutrino-driven shock, radioactive light and remnants

Problem

A Type II supernova's bolometric tail luminosity is measured to be L=6.8×1033 WL = 6.8\times10^{33}\,\mathrm{W} at t=350t = 350 days after explosion. SN 1987A's tail luminosity was L87A=1.7×1034 WL_{87A} = 1.7\times10^{34}\,\mathrm{W} at t87A=200t_{87A} = 200 days, corresponding to a nickel-56 mass of MNi,87A=0.07 M⊙M_{\rm Ni,87A} = 0.07\,M_\odot. Beyond about 100100 days, nickel-56 (mean lifetime 8.88.8 days) has essentially all decayed, and the tail is powered by cobalt-56 decay alone, with mean lifetime τCo=111.3 days\tau_{\rm Co} = 111.3\,\mathrm{days}. Assume the gamma rays from cobalt-56 decay are fully absorbed and thermalised in both events. Estimate the nickel-56 mass produced in this supernova.

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