19日上午徐智坚在查看拍摄的超新星搜索图片中发现了一个疑似目标，经群内诸位高手建议补拍一下再做上报，晚上进过补拍确认为真实未知目标，立即上报
POSSIBLE SUPERNOVA IN PGC 62237
Zhijian Xu(Nanjing,Jiangsu,China) and Xing Gao (Urumqi,Xinjiang,China), report the discovery of a possible supernova (mag approximately 17.9) on a 40-s survey image (limiting mag about 18.8)taken by Xing Gao in Xingming ObservationSky Survey(C42) around Aug. 18.80979 UT. using an unfiltered CCD ( + Celestron C14 Schmidt-Cassegrain telescope D=350-mm @f/6.9 ). The new object approximately located at R.A. =18h 40m 28s.84 Decl.=+36°07’17”.4(equinox 2000.0). Which is about 13.6″ west and 12.2″ south of the center of the PGC 62237.Nothing is visible at this position on archival images taken on Aug. 7(limiting mag 19.0) or on the DSS(POSS2/UKSTU Red) from Aug. 20,1992(limiting mag about 19.8)
NET USNO-B1.0
XM48ZX C2012 08 18.80979 18 40 28.84 +36 07 17.4 17.9 V C42
All images can be seen from: http://www.xjltp.com/XOSS/XM48ZX/XM48ZX.htm
C42,Xingming Observatory,Mt. Nanshan. Observers Z.Xu,X.Gao,Measurers Z.Xu 0.36-m f/6.9 Schmidt-Cassegrain telescope and CCD.
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Electronic Telegram No. 3212
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.
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Prepared using the Tamkin Foundation Computer Network
SUPERNOVA 2012ek IN PGC 62237 = PSN J18402884+3607174
Zhijian Xu, Nanjing, Jiangsu, China; and Xing Gao, Urumqi, Xinjiang,
China, report the discovery of a possible supernova (mag approximately 17.9)
on a 40-s unfiltered CCD image (limiting mag about 18.8) taken by Xing Gao
in the course of the Xingming Sky Survey around Aug. 18.810 UT using a
0.36-m f/6.9 Celestron C14 telescope at Mt. Nanshan. The new object is
approximately located at R.A. = 18h40m28s.84, Decl. = +36d07’17”.4 (equinox
2000.0; reference stars from USNO-B1.0 catalogue), which is about 13″.6
west and 12″.2 south of the center of the PGC 62237. Nothing is visible at
this position on a red Digitized Sky Survey plate from 1992 Aug. 20
(limiting mag about 19.8). The Xingming images are posted at website URL
http://www.xjltp.com/XOSS/XM48ZX/XM48ZX.htm. The object was designated PSN
J18402884+3607174 when it was posted at the Central Bureau’s TOCP webpage
and is here designated SN 2012ek based on the spectroscopic confirmation
reported below. Additional CCD magnitudes for 2012ek (unfiltered unless
noted otherwise): 2012 Aug. 7, [19.0 (Xu and Gao); Aug. 19.64, 17.9 (Xu
and Gao; image posted at the following website URL:
http://www.flickr.com/photos/75341417@N06/7816496822/in/photostream);
Aug. 19.896, 17.8 (Fabio Briganti and Fabio Martinelli, Celestron 14
telescope; independent discovery in the course of survey of the Italian
Supernovae Search Project); Aug. 20.206, 18.1 (J. Brimacombe, Cairns,
Australia; remotely using a 51-cm RCOS telescope + STL11K camera +
luminance filter at the New Mexico Skies Observatory near Mayhill, NM,
U.S.A.; position end figures 28s.92, 16″.6; image posted at
http://www.flickr.com/photos/43846774@N02/7824016820/); Aug. 20.62, 17.7
(Xu and Gao).
M. Turatto, S. Benetti, A. Pastorello, L. Tomasella, M. Fiaschi, P.
Ochner, E. Cappellaro, and S. Valenti, Osservatorio Astronomico di Padova,
Istituto Nazionale di Astrofisica, report that a spectrogram of PSN
J18402884+3607174 = SN 2012ek, obtained on Aug. 21.79 UT with the Asiago
1.82-m Copernico Telescope (+ AFOSC; range 340-820 nm; resolution 1.4 nm),
indicates that it is a type-Ib supernova. Adopting for the host galaxy
(PGC 62237) a redshift z = 0.028563 (Freudling et al. 1995, A.Ap. Suppl.
112, 429; via NED), comparison with a library of supernovae spectra via
GELATO (Harutyuyan et al. 2008, A.Ap. 488, 383) shows close similarities
of the spectrum of 2012ek to spectra of several type-Ib supernovae one week
after maximum.
NOTE: These ‘Central Bureau Electronic Telegrams’ are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2012 CBAT
2012 August 28 (CBET 3212) Michael Rudenko