Ground-based and JWST Observations of SN 2022pul. I. Unusual Signatures of Carbon, Oxygen, and Circumstellar Interaction in a Peculiar Type Ia Supernova

Matthew R. Siebert, Lindsey A. Kwok, Joel Johansson, Saurabh W. Jha, Stéphane Blondin, Luc Dessart, Ryan J. Foley, D. John Hillier, Conor Larison, Rüdiger Pakmor, Tea Temim, Jennifer E. Andrews, Katie Auchettl, Carles Badenes, Barnabas Barna, K. Azalee Bostroem, Max J. Brenner Newman, Thomas G. Brink, María José Bustamante-Rosell, Yssavo Camacho-NevesAlejandro Clocchiatti, David A. Coulter, Kyle W. Davis, Maxime Deckers, Georgios Dimitriadis, Yize Dong, Joseph Farah, Alexei V. Filippenko, Andreas Flörs, Ori D. Fox, Peter Garnavich, Estefania Padilla Gonzalez, Or Graur, Franz Josef Hambsch, Griffin Hosseinzadeh, D. Andrew Howell, John P. Hughes, Wolfgang E. Kerzendorf, Xavier K. Le Saux, Keiichi Maeda, Kate Maguire, Curtis McCully, Cassidy Mihalenko, Megan Newsome, John T. O'Brien, Jeniveve Pearson, Craig Pellegrino, Justin D.R. Pierel, Abigail Polin, Armin Rest, César Rojas-Bravo, David J. Sand, Michaela Schwab, Melissa Shahbandeh, Manisha Shrestha, Nathan Smith, Louis Gregory Strolger, Tamás Szalai, Kirsty Taggart, Giacomo Terreran, Jacco H. Terwel, Samaporn Tinyanont, Stefano Valenti, József Vinkó, J. Craig Wheeler, Yi Yang, Wei Kang Zheng, Chris Ashall, James M. DerKacy, Lluís Galbany, Peter Hoeflich, Eric Hsiao, Thomas de Jaeger, Jing Lu, Justyn Maund, Kyle Medler, Nidia Morrell, Benjamin J. Shappee, Maximilian Stritzinger, Nicholas Suntzeff, Michael Tucker, Lifan Wang

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Nebular-phase observations of peculiar Type Ia supernovae (SNe Ia) provide important constraints on progenitor scenarios and explosion dynamics for both these rare SNe and the more common, cosmologically useful SNe Ia. We present observations from an extensive ground- and space-based follow-up campaign to characterize SN 2022pul, a super-Chandrasekhar mass SN Ia (alternatively “03fg-like” SN), from before peak brightness to well into the nebular phase across optical to mid-infrared (MIR) wavelengths. The early rise of the light curve is atypical, exhibiting two distinct components, consistent with SN Ia ejecta interacting with dense carbon-oxygen (C/O)-rich circumstellar material (CSM). In the optical, SN 2022pul is most similar to SN 2012dn, having a low estimated peak luminosity (MB = −18.9 mag) and high photospheric velocity relative to other 03fg-like SNe. In the nebular phase, SN 2022pul adds to the increasing diversity of the 03fg-like subclass. From 168 to 336 days after peak B-band brightness, SN 2022pul exhibits asymmetric and narrow emission from [O I] λλ6300, 6364 (FWHM ≈ 2000 km s−1), strong, broad emission from [Ca II] λλ7291, 7323 (FWHM ≈ 7300 km s−1), and a rapid Fe III to Fe II ionization change. Finally, we present the first ever optical-to-MIR nebular spectrum of an 03fg-like SN Ia using data from JWST. In the MIR, strong lines of neon and argon, weak emission from stable nickel, and strong thermal dust emission (with T ≈ 500 K), combined with prominent [O I] in the optical, suggest that SN 2022pul was produced by a white dwarf merger within C/O-rich CSM.

Original languageEnglish (US)
Article numberad0975
JournalAstrophysical Journal
Issue number1
StatePublished - Jan 1 2024

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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