2015A&A...581L...4K

We present our findings on a supernova (SN) impostor, SNHunt248, based on optical and near-IR data spanning ∼15yr before discovery, to ∼1yr post-discovery. The light curve displays three distinct peaks, the brightest of which is at M_R ~-15.0mag. The post-discovery evolution is consistent with the ejecta from the outburst interacting with two distinct regions of circumstellar material. The 0.5-2.2µm spectral energy distribution at -740d is well-matched by a single 6700K 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 ~±1mag. At current epochs (∼1yr post-outburst), the absolute magnitude (M_R~-9mag) is just below the faintest observed historical absolute magnitude ∼10yr before discovery.