2012CBET.3029....1R

D. Rich, Hampden, ME, USA, reports his discovery of an apparent supernova (mag about 18.3) on unfiltered CCD frames (limiting mag 19.0) taken with a 0.41-m reflector on Feb. 20.120 UT. The new object is located at R.A. = 9:07:58.83, Decl. = +41:42:19.9 (equinox 2000.0), which is about 5".9 east and 12".1 south of the center of NGC 2755. The variable was designated PSN J09075883+4142199 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2012ai based on the spectroscopic confirmation reported below. Additional approximate CCD magnitudes (unfiltered unless otherwise noted) for 2012ai: 1989 Dec. 8, [20.5 (Palomar Sky Survey, red plate, via Digital Sky Survey; reported by Rich); 1990 Jan. 28, [21.0 (Palomar Sky Survey, blue plate; reported by Rich); 2012 Jan. 31.113, [19.0 (Rich); Feb. 18.899, 17.7 (Ron Arbour, South Wonston, Hants., England; 35-cm f/6 reflector; pre-discovery image; position end figures 58s.82, 19".3); 21.004, 17.8 (Rich); 21.122, 17.5 (R. A. Koff, Bennett, CO, USA; Meade 0.25-m f/10 reflector + Apogee AP-47p camera; limiting magnitude 19.5; position end figures 58s.73, 20".2; UCAC3 reference stars); 21.337, 19.1 (Joseph Brimacombe, Cairns, Australia; luminance filter; position end figures 58s.85, 20".2; image posted at URL http://www.flickr.com/photos/43846774@N02/6919932843/).

S. Benetti, A. Pastorello, L. Tomasella, and S. Valenti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, report that a spectrogram of PSN J09075883+4142199 = SN 2012ai, obtained on Feb. 22.88 UT with the 1.82-m Copernico Telescope (+ AFOSC; range 340-790 nm, resolution 2.2 nm), indicates that it is a type-II supernova. Comparison with a library of supernovae spectra via GELATO (Harutyuyan et al. 2008, A.Ap. 488, 383) gives a best fit with type-II supernovae soon after explosion, assuming a recession velocity for the host galaxy of 7543 km/s (SDSS 2004, via NED).