SN 2018fif: The explosion of a large red supergiant discovered in its infancy by the Zwicky transient facility

Maayane T. Soumagnac, Noam Ganot, Ido Irani, Avishay Gal-Yam, Eran O. Ofek, Eli Waxman, Jonathan Morag, Ofer Yaron, Steve Schulze, Yi Yang, Adam Rubin, S. Bradley Cenko, Jesper Sollerman, Daniel A. Perley, Christoffer Fremling, Peter Nugent, James D. Neill, Emir Karamehmetoglu, Eric C. Bellm, Rachel J. BruchRick Burruss, Virginia Cunningham, Richard Dekany, V. Zach Golkhou, Matthew J. Graham, Mansi M. Kasliwal, Nicholas P. Konidaris, Shrinivas R. Kulkarni, Thomas Kupfer, Russ R. Laher, Frank J. Masci, Reed Riddle, Mickael Rigault, Ben Rusholme, Jan van Roestel, Barak Zacka

Research output: Contribution to journalArticlepeer-review


High-cadence transient surveys are able to capture supernovae closer to their first light than ever before. Applying analytical models to such early emission, we can constrain the progenitor stars’ properties. In this paper, we present observations of SN 2018fif (ZTF 18abokyfk). The supernova was discovered close to first light and monitored by the Zwicky Transient Facility (ZTF) and the Neil Gehrels Swift Observatory. Early spectroscopic observations suggest that the progenitor of SN 2018fif was surrounded by relatively small amounts of circumstellar material compared to all previous cases. This particularity, coupled with the high-cadence multiple-band coverage, makes it a good candidate to investigate using shock-cooling models. We employ the SOPRANOS code, an implementation of the model by Sapir & Waxman and its extension to early times by Morag et al. Compared with previous implementations, SOPRANOS has the advantage of including a careful account of the limited temporal validity domain of the shock-cooling model as well as allowing usage of the entirety of the early UV data. We find that the progenitor of SN 2018fif was a large red supergiant with a radius of R = 744.0-+128.0183.0 R and an ejected mass of Mej = 9.3-+5.80.4 M. Our model also gives information on the explosion epoch, the progenitor’s inner structure, the shock velocity, and the extinction. The distribution of radii is double-peaked, with smaller radii corresponding to lower values of the extinction, earlier recombination times, and a better match to the early UV data. If these correlations persist in future objects, denser spectroscopic monitoring constraining the time of recombination, as well as accurate UV observations (e.g., with ULTRASAT), will help break the extinction/radius degeneracy and independently determine both.

Original languageEnglish
Article number6
Number of pages15
JournalAstrophysical Journal
Issue number1
StatePublished - 10 Oct 2020

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'SN 2018fif: The explosion of a large red supergiant discovered in its infancy by the Zwicky transient facility'. Together they form a unique fingerprint.

Cite this