[IAUC] CBET 4116: 20150706 : SUPERNOVA 2015K IN NGC 7712 = PSN J23355226+2336521

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                                                  Electronic Telegram No. 4116
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau en eps.harvard.edu (alternate cbat en iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2015K IN NGC 7712 = PSN J23355226+2336521
     S. Nakano, Sumoto, Japan, reports the discovery by Koichi Itagaki
(Teppo-cho, Yamagata, Japan) of an apparent supernova (mag 16.3) on an
unfiltered CCD frame (limiting mag 18.0) taken on Apr. 25.786 UT using a
0.50-m f/6 reflector.  The new object is located at R.A. = 23h35m52s.26,
Decl. = +23d36'52".1 (equinox 2000.0), which is 8".4 east and 15".2 south
of the nucleus of the galaxy NGC 7712.  Itagaki has posted his discovery
image at website URL http://k-itagaki.jp/images/7712.jpg.  The variable was
designated PSN J23355226+2336521 when it was posted at the Central Bureau's
TOCP webpage and is here designated SN 2015K based on the spectroscopic
confirmation reported below.  Additional CCD magnitudes for 2015K:  2006 Aug.
3.59, [19.5 (Itagaki; 0.60-m f/5.7 reflector); 26.755, 16.0 (T. Noguchi,
Katori, Chiba-ken, Japan; 0.23-m f/6.3 reflector; limiting mag 18.0; position
end figures 52s.21, 53".3; UCAC4 reference stars; communicated by Nakano;
image posted at URL http://park8.wakwak.com/~ngc/images/PSNinNGC7712.jpg);
27.804, 16.5 (J. Brimacombe, Cairns, Australia; remotely with a 33-cm RCOS
telescope at the Savannah Skies Observatory in N. Queensland, Australia;
position end figures 52s.26, 52".6; image posted at website URL
https://www.flickr.com/photos/43846774@N02/17305785961/); May 19.060, 17.3
(G. Masi; remotely with a 43-cm telescope at Ceccano, Italy; position end
figures 52s.24, 52".2).

     T. Nakaoka, R. Itoh, K. Takaki, M. Kawabata, and K. S. Kawabata,
Hiroshima University; and M. Yamanaka, Konan University, obtained a
low-resolution optical spectrogram (range 450-900 nm) of PSN J23355226+2336521
= SN 2015K on Apr. 26.8 UT with the 1.5-m Kanata telescope (+ HOWPol) at the
Higashi-Hiroshima Observatory.  The spectrum shows absorption of Na I D, O I
777.4-nm, and a P-Cygni profile of the Ca II near-infrared triplet,
suggesting that this is a type-Ic supernova.  The absorption component of
the Ca II infrared triplet line is blueshifted by around 8000 km/s.  A
comparison with a library of supernova spectra using GELATO (Harutyunyan et
al. 2008, A.Ap. 488, 383) reveals that the spectrum gives a good match to
type-Ic supernovae, such as SN 2004aw at 3-4 weeks past B-band maximum.


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                         (C) Copyright 2015 CBAT
2015 July 6                      (CBET 4116)              Daniel W. E. Green