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. Smith; J. Sollerman; L. Tomasella

doi:10.1051/0004-6361/201526631

paper

On the triple peaks of SNHunt248 in NGC 5806

arXiv:1508.04730 · doi:10.1051/0004-6361/201526631

Abstract

We present our findings on a supernova (SN) impostor, SNHunt248, based on optical and near-IR data spanning $\sim$ 15 yrs before discovery, to $\sim$ 1 yr post-discovery. The light curve displays three distinct peaks, the brightest of which is at $M_{R} \sim - 15.0$ 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 $μ$ m spectral energy distribution at -740 d is well-matched by a single 6700 K blackbody with $lo g (L / L_{⊙}) \sim 6.1$ . 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 $\sim \pm 1$ mag. At current epochs ( $\sim$ 1 yr post-outburst), the absolute magnitude ( $M_{R} \sim - 9$ mag) is just below the faintest observed historical absolute magnitude $\sim$ 10 yrs before discovery.

7 pages, 3 figures, accepted for A&A Letters

On the triple peaks of SNHunt248 in NGC 5806

Abstract

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