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Supernova Light Curve

What you are seeing: the bolometric light curve L(t) of a supernova as the hero panel, with the selected event overlaid on the other type and on the fully trapped radioactive power its tail decays onto. The 56Ni -> 56Co -> 56Fe decay chain that powers the curve is plotted below, and a supporting fireball expands homologously (r = v_ej t) and brightens with L(t). Toggle between SN 2011fe (Type Ia, the standard candle) and SN 1987A (Type II core-collapse); scroll to zoom the fireball

Figure 1. Supernova light curve: bolometric L(t) as the hero panel (selected type, the other type, and the fully trapped radioactive power), the Ni / Co / Fe mass partition that powers it, and a supporting homologously expanding fireball. Method: Arnett-1982 decay-chain heating with a diffusion-trapping factor; closed-form Bateman equations for the chain mass partition.
SN preset2011fe
56Ni mass (M_sun)0.60
diffusion time (d)14
v_ej (km/s)11000

WHAT TO TRY

  • Switch between a Type Ia and SN 1987A: the fireball expands homologously and the light curve is powered by the radioactive decay chain 56Ni to 56Co to 56Fe, the engine behind the peak and tail.
  • Raise the 56Ni mass: more radioactive fuel makes a brighter peak, the relation that makes Type Ia supernovae standardizable candles.
  • Lengthen the diffusion time: photons take longer to leak out of the dense ejecta, broadening the light curve. The late tail tracks the cobalt decay directly.