On the triple peaks of SNHunt248 in NGC 5806

E. Kankare*, R. Kotak, A. Pastorello, M. Fraser, S. Mattila, S. J. Smartt, A. Bruce, K. C. Chambers, N. Elias-Rosa, H. Flewelling, C. Fremling, J. Harmanen, M. Huber, A. Jerkstrand, T. Kangas, H. Kuncarayakti, M. Magee, E. Magnier, J. Polshaw, K. W. SmithJ. Sollerman, L. Tomasella

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We present our findings on a supernova (SN) impostor, SNHunt248, based on optical and near-IR data spanning similar to 15 yr before discovery, to similar to 1 yr post-discovery. The light curve displays three distinct peaks, the brightest of which is at MR similar to -15.0 mag. The post-discovery evolution is consistent with the ejecta from the outburst interacting with two distinct regions of circumstellar material. The 0.5-2.2 mu m spectral energy distribution at -740 d is well-matched by a single 6700 K blackbody with log(L/L-circle dot) similar to 6.1. This temperature and luminosity support previous suggestions of a yellow hypergiant progenitor; however, we find it to be brighter than the brightest and most massive Galactic late-F to early-G spectral type hypergiants. Overall the historical light curve displays variability of up to similar to +/- 1 mag. At current epochs (similar to 1 yr post-outburst), the absolute magnitude (MR similar to -9 mag) is just below the faintest observed historical absolute magnitude similar to 10 yr before discovery.

Original languageEnglish
Article numberL4
Number of pages7
JournalAstronomy & Astrophysics
Volume581
Early online date7 Sep 2015
DOIs
Publication statusE-pub ahead of print - 7 Sep 2015

Keywords

  • stars: massive
  • stars: mass-loss
  • supernovae: general
  • supernovae: individual: SNHunt248
  • DIGITAL SKY SURVEY
  • CORE-COLLAPSE
  • SN
  • SUPERNOVA
  • OUTBURST

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