On the triple peaks of SNHunt248 in NGC 5806
Abstract
We present our findings on a supernova (SN) impostor, SNHunt248, based on optical and near-IR data spanning ~15 yr before discovery, to ~1 yr post-discovery. The light curve displays three distinct peaks, the brightest of which is at MR ~ -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 μm 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 (MR ~ - 9 mag) is just below the faintest observed historical absolute magnitude ~10 yr before discovery.
Tables 1-4 are available in electronic form at http://www.aanda.org- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 2015
- DOI:
- 10.1051/0004-6361/201526631
- arXiv:
- arXiv:1508.04730
- Bibcode:
- 2015A&A...581L...4K
- Keywords:
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- stars: massive;
- stars: mass-loss;
- supernovae: general;
- supernovae: individual: SNHunt248;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 7 pages, 3 figures, accepted for A&