Volume 581, September 2015
|Number of page(s)||7|
|Published online||07 September 2015|
On the triple peaks of SNHunt248 in NGC 5806⋆
1 Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, BT7 1NN, UK
2 INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
3 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
4 Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, 21500 Piikkiö, Finland
5 Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Väisäläntie 20, 21500 Piikkiö, Finland
6 Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
7 Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
8 Department of Astronomy, The Oskar Klein Center, Stockholm University, AlbaNova, 10691 Stockholm, Sweden
9 Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma, Spain
10 Millennium Institute of Astrophysics, Casilla 36-D, Santiago, Chile
11 Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
Received: 29 May 2015
Accepted: 17 August 2015
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.
Key words: stars: massive / stars: mass-loss / supernovae: general / supernovae: individual: SNHunt248
Tables 1–4 are available in electronic form at http://www.aanda.org
© ESO, 2015
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