The Iron Yield of Core-collapse Supernovae

Abstract

We present a systematic analysis of 191 stripped-envelope supernovae (SE SNe), aimed at computing their 56Ni masses from the luminosity in their radioactive tails ( M Ni tail ) and/or in their maximum light, and the mean 56Ni and iron yields of SE SNe and core-collapse SNe. Our sample consists of SNe IIb, Ib, and Ic from the literature and from the Zwicky Transient Facility Bright Transient Survey. To calculate luminosities from optical photometry, we compute bolometric corrections using 49 SE SNe with optical and near-IR photometry, and develop corrections to account for the unobserved UV and IR flux. We find that the equation of Khatami & Kasen for radioactive 56Ni-powered transients with a single free parameter does not fit the observed peak time–luminosity relation of SE SNe. Instead, we find a correlation between M Ni tail , peak time, peak luminosity, and decline rate, which allows for measuring individual 56Ni masses to a precision of 14%. Applying this method to the whole sample, we find, for SNe IIb, Ib, and Ic, mean 56Ni masses of 0.066 ± 0.006, 0.082 ± 0.009, and 0.132 ± 0.011 M ⊙, respectively. After accounting for their relative rates, for SE SNe as a whole, we compute mean 56Ni and iron yields of 0.090 ± 0.005 and 0.097 ± 0.007 M ⊙, respectively. Combining these results with the recent Type II SN mean 56Ni mass derived by Rodríguez et al., core-collapse SNe, as a whole, have mean 56Ni and iron yields of 0.055 ± 0.006 and 0.058 ± 0.007 M ⊙, respectively. We also find that radioactive 56Ni-powered models typically underestimate the peak luminosity of SE SNe by 60%–70%, suggesting the presence of an additional power source contributing to the luminosity at peak.

SN 2022oqm–A Ca-rich Explosion of a Compact Progenitor Embedded in C/O Circumstellar Material

“…While 56 Ni decay can account for the late-time behavior of the light curve, an additional powering mechanism is required to explain the early-time luminosity. The inferred 56 Ni mass, kinetic energy, and ejected mass are within the distribution of values found for SNe Ic by Barbarino et al (2021) and Rodríguez et al (2023), with the ejecta mass lying toward the low end of the mass distribution. A rough order-of-magnitude estimate for the γ-ray escape time t γ and the diffusion time τ m comes from demanding an optical depth of unity for γ-ray escape, and a dynamical timescale for the diffusion of order c/v.…”

Physical Correlations and Predictions Emerging from Modern Core-collapse Supernova Theory

“…The theoretical correlation between 56 Ni and explosion energy has been seen before (e.g., Sukhbold et al 2016), but not in the context of such a large 3D model suite carried to, or near to, the asymptotic state. Such a correlation is also strongly suggested by observations (Rodríguez et al 2023). The intriguing correlation between explosion energy and neutron star gravitational mass is new in the detailed 3D modeling context but was anticipated in the 2D results of Nakamura et al (2015) and in the semianalytic modeling of Müller et al (2016a).…”

“…More details concerning the formalism can be found in Wang & Burrows (2024). This, too, is one of the central results of this paper, but the correlation between the two has already been anticipated theoretically (e.g., Sukhbold et al 2016) and observed astronomically (Rodríguez et al 2023). The left panel provides the 56 Ni correlation with explosion energy, with the range of predicted energies due to the fact that not all 3D models have yet asymptoted to their final values indicated.…”

“…The left panel provides the 56 Ni correlation with explosion energy, with the range of predicted energies due to the fact that not all 3D models have yet asymptoted to their final values indicated. The right panel shows the same numerical data, but superposed on the Rodríguez et al (2023) measurements. The overlap between the two suggests a reasonable concordance, though both trends are subject to natural variation.…”

A Perspective on the Milky Way Bulge Bar as Seen from the Neutron-capture Elements Cerium and Neodymium with APOGEE

“…To compare the contributions of neutron-capture processes with core-collapse and Type Ia supernova yields in the bulge population, we investigate Ce and Nd abundances relative to Mg (a tracer of core-collapse supernovae, Woosley & Weaver 1995) and Mn (a pristine tracer of supernovae Type Ia, Iwamoto et al 1999;Kobayashi et al 2006). Iron is produced in supernovae Type Ia, like Mn, but presents other relevant production in core-collapse supernovae (e.g., Rodríguez et al 2023).…”