Type II supernovae progenitor and ejecta properties from the total emitted light, ET

Understand

It was recently shown that the bolometric light curves of type II supernovae (SNe) allow an accurate and robust measurement of the product of the radiation energy in the ejecta, $E_r$, and the time since the explosion, $t$, at early phases ($t\lesssim 10d$) of the homologous expansion.

• This observable, denoted here $ET \equiv E_rt$ is constant during that time and depends only on the progenitor structure and explosion energy.
• We use a 1D hydrodynamic code to find $ET$ of simulated explosions of 145 red supergiant progenitors obtained using the stellar evolution code MESA, and relate this observable to the properties of the progenitor and the explosion energy.
• We show that $ET$ probes only the properties of the envelope (velocity, mass and initial structure), similarly to other observables that rely on the photospheric phase emission.