Constraints on the Explosion Timescale of Core-collapse Supernovae Based on Systematic Analysis of Light Curves

Abstract

The explosion mechanism of core-collapse supernovae is not fully understood yet. In this work, we give constraints on the explosion timescale based on 56Ni synthesized by supernova explosions. First, we systematically analyze multiband light curves of 82 stripped-envelope supernovae (SESNe) to obtain bolometric light curves, which is among the largest samples of the bolometric light curves of SESNe derived from the multiband spectral energy distribution. We measure the decline timescale and the peak luminosity of the light curves and estimate the ejecta mass (M ej) and 56Ni mass (M Ni) to connect the observed properties with the explosion physics. We then carry out one-dimensional hydrodynamics and nucleosynthesis calculations, varying the progenitor mass and the explosion timescale. From the calculations, we show that the maximum 56Ni mass that 56Ni-powered SNe can reach is expressed as M Ni ≲ 0.2 M ej. Comparing the results from the observations and the calculations, we show that the explosion timescale shorter than 0.3 s explains the synthesized 56Ni mass of the majority of the SESNe.

Monotonicity of the cores of massive stars

“…For Type II SNe showing lines of hydrogen in the spectrum, correlations have been suggested between 56 Ni ejecta mass, total ejecta mass, plateau luminosity, and expansion velocity (Hamuy 2003;Anderson et al 2014;Spiro et al 2014;Valenti et al 2015;Anderson 2019;Martinez et al 2022). Similarly, correlations among kinetic energy, ejecta mass, and 56 Ni ejecta mass have been found for the stripped-envelope SNe (SE-SNe) consisting of types IIb, Ib, and Ic (Lyman et al 2016;Taddia, F. et al 2018;Anderson 2019;Barbarino et al 2021, see also Meza & Anderson 2020;Saito et al 2022). Given that SN explosions can be defined as the solution to the initial value problem initiated by the collapse of the core of a massive star, the diversity and the correlations in the properties of the explosions should essentially come from the structure of the progenitor star.…”

Monotonicity of the Cores of Massive Stars

“…For Type II SNe showing lines of hydrogen in the spectrum, correlations have been suggested between 56 Ni ejecta mass, total ejecta mass, plateau luminosity, and expansion velocity (Hamuy 2003;Anderson et al 2014;Spiro et al 2014;Valenti et al 2015;Muller et al 2017b;Anderson 2019;Martinez et al 2022). Similarly, correlations among kinetic energy, ejecta mass, and 56 Ni ejecta mass have been found for the strippedenvelope SNe (SE-SNe) consisting of Types IIb, Ib, and Ic (Lyman et al 2016;Taddia et al 2018;Anderson 2019;Barbarino et al 2021, see also Meza & Anderson 2020;Saito et al 2022). Given that SN explosions can be defined as the solution to the initial value problem initiated by the collapse of the core of a massive star, the diversity and the correlations in the properties of the explosions should essentially come from the structure of the progenitor star.…”

Nucleosynthesis of Binary-stripped Stars

“…In our default model, energy is then injected over the inner 0.01 M e and over 0.0045 s. We inject sufficient energy to bring the total energy of the star (the sum of the kinetic plus thermal energy minus the gravitational binding energy) to 10 51 erg s −1 . While there is some evidence for choosing different explosion parameters between stripped-envelope SNe and nonstripped SNe (Saito et al 2022), we chose to use a constant set of parameters to minimize the parameter space explored. In Section 5.4 we show the uncertainty introduced into the final yields due to differences in the explosion parameters.…”