A meta-analysis of core-collapse supernova⁵⁶Ni masses

Abstract

Context. A fundamental property determining the transient behaviour of core-collapse supernovae (CC SNe) is the amount of radioactive 56 Ni synthesised in the explosion. Using established methods, this is a relatively easy parameter to extract from observations. Aims. I provide a meta analysis of all published 56 Ni masses for CC SNe. Methods. Collating a total of 258 literature 56 Ni masses I compare distributions of the main CC SN types: SNe II; SNe IIb; SNe Ib; SNe Ic; and SNe IcBL. Results. Using these published values, I calculate a median 56 Ni mass of 0.032 M for SNe II (N=115), 0.102 M (N=27) for SNe IIb, SNe Ib = 0.163 M (N=33), SNe Ic = 0.155 M (N=48), and SNe IcBL = 0.369 M (N=32). On average, stripped-enevelope SNe (SE-SNe: IIb; Ib; Ic; and Ic-BL) have much higher values than SNe II. These observed distributions are compared to those predicted from neutrino-driven explosion models. While the SN II distribution follows model predictions, the SE-SNe have a significant fraction of events with 56 Ni masses much higher than predicted.Conclusions. If the majority of published 56 Ni masses are to be believed, these results imply significant differences in the progenitor structures and/or explosion properties between SNe II and SE-SNe. However, such distinct progenitor and explosion properties are not currently favoured in the literature. Alternatively, the popular methods used to estimate 56 Ni masses for SE-SNe may not be accurate. Possible issues with these methods are discussed, as are the implications of true 56 Ni mass differences on progenitor properties of different CC SNe.

The Explosion of Helium Stars Evolved with Mass Loss

“…) is 0.14 +0.04 −0.04 M for Type Ib and 0.16 +0.03 −0.10 M for Type Ic according toPrentice et al (2016) Lyman et al (2016). give slightly larger values, 0.17 ± 0.16 M for Type Ib and 0.22 ± 0.16 M for Type Ic Anderson (2019). also gives similar values based on a literature survey, 0.163 M for Type Ib and 0.155 M for Type Ic.…”

“…All in all though, it seems that neutrino-powered explosions as parametrized here, have trouble making enough 56 Ni to explain the light curves of many of the brighter ordinary Type Ib and Ic supernovae reported in the literature. A similar conclusion was reached by Anderson (2019). This flies in the face of current convention which states that all such supernovae come from binaries, are neutrino powered, and have radioactive-powered light curves, and warrants some discussion.…”

“…Whatever is done for Type Ib and Ic models must also be done for Type IIp models which have very similar core structure and explosion characteristics ( §4.5 and Appendix A). There are limits from iron nucleosynthesis ( §5), the 56 Ni produced in SN 1987A ( §5), the tails of the light curves of Type IIp supernovae (Anderson 2019), and the masses of neutron stars ( §6.1) that prohibit moving the mass cut in too deep. So other explanations of the bright light curves of Type Ib and Ic supernovae are also explored here -an embedded magnetar and circumstellar interaction.…”

Supernovae Ib and Ic from the explosion of helium stars

“…Part of this tension arises from a few outliers with erroneous estimates of the 56 Ni mass, for example because of an overestimate of the reddening (e.g., SN 2005hg claimed by Lyman et al 2016 to have 0.66 M of 56 Ni but this estimate relies on an adopted reddening E(B−V) of 0.685 mag, when in fact the reddening is low and probably about 0.1 mag -see below). However, even without these outliers, an offset remains in the distribution of 56 Ni masses between SNe Ibc and SNe II-P (Anderson 2019;Meza & Anderson 2020).…”

DES16C3cje: A low-luminosity, long-lived supernova

“…where M( 56 Ni) 87A = 0.075 ± 0.005 M is the 56 Ni mass synthesised by SN 1987A (Arnett 1996) and 87A is the bolometric luminosity at a comparable epoch. This comparison gives ( 56 Ni) 16cje ≈ 0.068 M , a comparatively large value for typical SN II, but within the range of SN 1987A-like objects (Müller et al 2017;Anderson 2019).…”