Padova-Asiago Supernova Group
Highlights
On the triple peaks of SNHunt248 in NGC 5806
E. Kankare et al. 2015 A&A 581, L4 (link to pdf)
We present our findings on a supernova (SN) impostor, SNHunt248, based on optical and near-IR data spanning 15 yrs before discovery, to 1 yr post-discovery. The light curve displays three distinct peaks, the brightest of which is at MR15.0 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 m spectral energy distribution at -740 d is well-matched by a single 6700 K blackbody with log(L/L)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 1 mag. At current epochs (1 yr post-outburst), the absolute magnitude (MR9 mag) is just below the faintest observed historical absolute magnitude 10 yrs before discovery. 64
E. Kankare et al. 2015 A&A 581, L4 (link to pdf)
We present our findings on a supernova (SN) impostor, SNHunt248, based on optical and near-IR data spanning 15 yrs before discovery, to 1 yr post-discovery. The light curve displays three distinct peaks, the brightest of which is at MR15.0 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 m spectral energy distribution at -740 d is well-matched by a single 6700 K blackbody with log(L/L)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 1 mag. At current epochs (1 yr post-outburst), the absolute magnitude (MR9 mag) is just below the faintest observed historical absolute magnitude 10 yrs before discovery. 64
