SN 2012ds (A.R. 16 23 45.92, Dec. +09 47 12.3), scoperta il 16 luglio 2012 nella galassia pgc 58009 (offset 12E 5S), magnitudine 17.4.
SN scoperta da F. Ciabattari ed E. Mazzoni con il telescopio Newton da 50cm dell'Osservatorio di Monte Agliale (Lucca).
Electronic Telegram No. 3185
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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SUPERNOVA 2012ds IN PGC 58009 = PSN J16234592+0947123
F. Ciabattari, E. Mazzoni, and M. Rossi, Borgo a Mozzano, Italy, report
their discovery of an apparent supernova (mag 17.4) on unfiltered CCD images
(limiting magnitude 19.5) obtained on July 16.97 and 17.85 UT with a 0.5-m
Newtonian telescope in the course of the Italian Supernovae Search Project.
The new object is located at R.A. = 16h23m45s.92, Decl. = +9d47'12".3 (equinox
2000.0; astrometry with respect to UCAC-2 stars), which is 12" east and 5"
south of the center of the galaxy PGC 58009. Nothing is visible at this
position on the discoverers' images of the same field from June 2010 (limiting
magnitude 19.0). The variable was designated PSN J16234592+0947123 when it
was posted at the Central Bureau's TOCP webpage and is here designated SN
2012ds based on the spectroscopic confirmation reported below. Additional
magnitudes reported for 2012ds: 1987 June 28, [20.3 (Digitized Sky Survey,
Palomar F plate; via Ciabattari); 1988 June 11, [20.3 (DSS, Palomar J plate;
via Ciabattari); 2012 July 17.942, 17.2 (Federica Luppi and Luca Buzzi,
Varese, Italy; 0.38-m f/6.8 reflector; position end figures 45s.89, 13".0;
reference stars from NOMAD catalogue; image posted at the following website
URL: http://www.astrogeo.va.it/pub/TOCP/PSN_P58009.jpg); July 18.263, 17.1
(Joseph 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 45s.90, 12".9; image posted at URL
http://www.flickr.com/photos/43846774@N02/7600562452/); July 18.852, R_c =
17.0 (Massimiliano Martignoni, Magnago, Italy; 0.25-m f/10 reflector; position
end figures 45s.91, 12".9); July 19.202, 16.4 (L. Elenin, Lyubertsy, Russia,
and I. Molotov, Moscow, Russia, remotely taken at the ISON-NM Observatory
near Mayhill, NM, USA, with a 0.45-m f/2.8 telescope; limiting mag about 20.0;
position end figures 45s.87 +/- 0".12, 12".9 +/- 0".13; reference stars from
NOMAD catalogue; image posted at the following website URL:
http://spaceobs.org/images/TOCP/PSNJ16234592+0947123-20120719.png).
L. Tomasella, S. Benetti, E. Cappellaro, P. Ochner, A. Pastorello, M.
Turatto, and S. Valenti, Osservatorio Astronomico di Padova, Istituto
Nazionale di Astrofisica, report that a spectrogram of PSN J16234592+0947123 =
2012ds, obtained on July 17.92 UT with the Asiago 1.82-m Copernico Telescope
(+ AFOSC; range 340-820 nm; resolution 2.4 nm), suggests that it is a normal
type-Ia supernova. Adopting for the host galaxy a redshift z = 0.03403 (Falco
et al. 1999, PASP, 111, 438; via NED), a comparison with a library of
supernovae spectra via GELATO (Harutyuyan et al. 2008, A.Ap. 488, 383) shows
that 2012ds is a type-Ia event soon 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 July 19 (CBET 3185) Daniel W. E. Green