SN 2023iop: An Extreme 1987A-like Supernova and the Death of Very Massive Stars
Abstract
Supernova (SN) 1987A showed that some hydrogen-rich core-collapse supernovae (SNe) rise slowly to peak, defining a distinct subclass. Wide-field surveys have uncovered more extreme members, such as OGLE-2014-SN-73, SN 2020faa, and SN 2023vbw, that challenge neutrino-driven explosion models. We present ultraviolet-to-infrared, radio, X-ray, and spectropolarimetric observations of SN 2023iop at z = 0.1020, the most extreme 87A-like event to date. It rose for ≳88 rest-frame days to Mr ≈ −20.1 mag, also placing it among the hydrogen-rich superluminous SNe, and radiated ≳4×1050 erg. Its spectra resemble those of typical Type II SNe and remain photospheric at ∼330 days post-maximum. Continuum polarization of 0.8-1.0% indicates an aspherical system. Hydrogen-rich pair-instability supernova (PISN) models of a 190 M⊙ star reproduce the light-curve up to 150 days after peak, but not the late-time emission. A late-time spectrum shows a feature near 7300 Å, tentatively identified as [Ni II] λ7378. The implied ≈0.02 M⊙ of stable 58Ni is reached only in the most massive PISN models. The low-mass host galaxy (∼108.2 M⊙) is consistent with a metal-poor progenitor as required by the PISN channel. Fallback accretion reproduces the light-curve morphology, but not the colors. We consider a pair-instability explosion the most plausible scenario, with the late-time light-curve excess powered by circumstellar interaction, which shows no signatures in the spectra. SN 2023iop shows that the most luminous 87A-like events occupy an underexplored region of massive-star evolution.
Related
- Extreme Stellar Death and Galaxy Feedback at z = 2: A Rest-frame Ultraviolet Characterization of the Strongly Lensed Superluminous Supernova 2025wny
- Supernova 1987A was a "failed supernova" twenty thousand years before its jet-driven explosion
- The physics of deep-interior convective shell boundaries in a massive pre-supernova star: Internal gravity wave mixing at the N2 peak
- Devoured by a Hairy Gargantua: Probing Massive Scalar Charges with Non-minimal Curvature Coupling with Extreme-Mass-Ratio Inspirals
- Extended gamma-ray emission in the vicinity of the Westerlund 1 massive star cluster and Kes 41 supernova remnant seen by the Fermi Large Area Telescope
BibTeX
@misc{schulze20262023iop,
title = {{SN 2023iop: An Extreme 1987A-like Supernova and the Death of Very Massive Stars}},
author = {Steve Schulze and Avinash Singh and Nikhil Sarin and Ofer Yaron and Jesper Sollerman and Takashi J. Moriya and Avishay Gal-Yam and Bart van Baal and Stan Barmentloo and Conor M. B. Omand and Hannah Wichern and Tuomas Kangas and Priscila J. Pessi and Adam A. Miller and Armin Rest and Lin Yan and Alexei V. Filippenko and Chang Liu and Miika Pursiainen and Yi Yang and Georgios Dimitriadis and Kishalay De and Seán J. Brennan and Thomas G. Brink and Ping Chen and Aleksandar Cikota and Felice Cusano and Nicholas Earley and Claes Fransson and Lluís Galbany and Anamaria Gkini and Anders Jerkstrand and Ragnhild Lunnan and Keiichi Maeda and Diego Paris and Andrea Rossi and Nabeel Rehemtulla and Claudia Skoglund and WeiKang Zheng and Alaa Alburai and Ke-Jung Chen and K-Ryan Hinds and Anjasha Gangopadhyay and Jonay Isaí Gonzalez-Hernandez and Assaf Horesh and Giorgos Leloudas and Eliana Palazzi and Daniel A. Perley and Frédérick Poidevin and Ramon Sanfeliu and Jacob L. Wise and Erez A. Zimmerman and Alice Cai and Joahan Jaimes and Ting-Wan Chen and Michael W. Coughlin and Richard Dekany and Ori D. Fox and Christoffer Fremling and Matthew J. Graham},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.27312},
eprint = {2610.27312},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.27312},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - SN 2023iop: An Extreme 1987A-like Supernova and the Death of Very Massive Stars
AU - Steve Schulze
AU - Avinash Singh
AU - Nikhil Sarin
AU - Ofer Yaron
AU - Jesper Sollerman
AU - Takashi J. Moriya
AU - Avishay Gal-Yam
AU - Bart van Baal
AU - Stan Barmentloo
AU - Conor M. B. Omand
AU - Hannah Wichern
AU - Tuomas Kangas
AU - Priscila J. Pessi
AU - Adam A. Miller
AU - Armin Rest
AU - Lin Yan
AU - Alexei V. Filippenko
AU - Chang Liu
AU - Miika Pursiainen
AU - Yi Yang
AU - Georgios Dimitriadis
AU - Kishalay De
AU - Seán J. Brennan
AU - Thomas G. Brink
AU - Ping Chen
AU - Aleksandar Cikota
AU - Felice Cusano
AU - Nicholas Earley
AU - Claes Fransson
AU - Lluís Galbany
AU - Anamaria Gkini
AU - Anders Jerkstrand
AU - Ragnhild Lunnan
AU - Keiichi Maeda
AU - Diego Paris
AU - Andrea Rossi
AU - Nabeel Rehemtulla
AU - Claudia Skoglund
AU - WeiKang Zheng
AU - Alaa Alburai
AU - Ke-Jung Chen
AU - K-Ryan Hinds
AU - Anjasha Gangopadhyay
AU - Jonay Isaí Gonzalez-Hernandez
AU - Assaf Horesh
AU - Giorgos Leloudas
AU - Eliana Palazzi
AU - Daniel A. Perley
AU - Frédérick Poidevin
AU - Ramon Sanfeliu
AU - Jacob L. Wise
AU - Erez A. Zimmerman
AU - Alice Cai
AU - Joahan Jaimes
AU - Ting-Wan Chen
AU - Michael W. Coughlin
AU - Richard Dekany
AU - Ori D. Fox
AU - Christoffer Fremling
AU - Matthew J. Graham
PY - 2026
DA - 2026/10/19
PB - arXiv
DO - 10.48550/arxiv.2610.27312
UR - https://arxiv.org/abs/2610.27312
AB - Supernova (SN) 1987A showed that some hydrogen-rich core-collapse supernovae (SNe) rise slowly to peak, defining a distinct subclass. Wide-field surveys have uncovered more extreme members, such as OGLE-2014-SN-73, SN 2020faa, and SN 2023vbw, that challenge neutrino-driven explosion models. We present ultraviolet-to-infrared, radio, X-ray, and spectropolarimetric observations of SN 2023iop at z = 0.1020, the most extreme 87A-like event to date. It rose for ≳88 rest-frame days to M_r ≈ −20.1 mag, also placing it among the hydrogen-rich superluminous SNe, and radiated ≳4×10^50 erg. Its spectra resemble those of typical Type II SNe and remain photospheric at ∼330 days post-maximum. Continuum polarization of 0.8-1.0% indicates an aspherical system. Hydrogen-rich pair-instability supernova (PISN) models of a 190 M_⊙ star reproduce the light-curve up to 150 days after peak, but not the late-time emission. A late-time spectrum shows a feature near 7300 Å, tentatively identified as [Ni II] λ7378. The implied ≈0.02 M_⊙ of stable ^58Ni is reached only in the most massive PISN models. The low-mass host galaxy (∼10^8.2 M_⊙) is consistent with a metal-poor progenitor as required by the PISN channel. Fallback accretion reproduces the light-curve morphology, but not the colors. We consider a pair-instability explosion the most plausible scenario, with the late-time light-curve excess powered by circumstellar interaction, which shows no signatures in the spectra. SN 2023iop shows that the most luminous 87A-like events occupy an underexplored region of massive-star evolution.
ER -