Psn J12211796+1130252 in NGC 4294

Alessandro Dimai, Cortina d'Ampezzo, Italy, reports the discovery of a variable star (mag 16.4) in four images taken on Feb. 8.116 UT with a 0.28-m f/6.3 telescope at the Col Drusci Observatory; the new object is located at R.A. = 12h21m17s.96, Decl. = +11d30'25".2 (equinox 2000.0), which is 11" south and slightly east of the center of NGC 4294 (and within 2" of a blue stellar association that is visible in blue Palomar Sky Survey plates. Dimai posted an image of PSN J12211796+1130252 at the following website URL: http://www.cortinastelle.it/T21-adimai-ngc4294-20130211_123144UT.jpg. The variable was designated PSN J12211796+1130252 when it was posted at the Central Bureau's TOCP webpage. Additional CCD magnitudes for PSN J12211796+1130252: Feb. 14.179, 17.9 (Federica Luppi and Luca Buzzi, Varese, Italy; 0.38-m f/6.8 reflector; unfiltered image; position end figures 17s.83, 27".7; reference stars from CMC-14 catalogue; a source is visible in Digitized Sky Survey images at position end figures 17s.80, 27".4; image posted at website URL http://www.astrogeo.va.it/pub/TOCP/PSN_N4294.jpg); 16.095, R_c = 17.5 (Massimiliano Martignoni, Magnago, Italy; 0.25-m f/10 reflector; position end figures 17s.80, 26".4). L. Tomasella, P. Ochner, S. Benetti, A. Pastorello, E. Cappellaro, L. Bedin, M. Turatto, S. Spiro, and L. Tartaglia, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica (INAF); A. Harutyunyan, Telescopio Nazionale Galileo (TNG); A. Dimai, Cortina d'Ampezzo, Italy, on behalf of the Italian Supernovae Search Project; M. T. Botticella, Osservatorio Astronomico di Capodimonte, INAF; G. Pignata and F. Bufano, Universidad Andres Bello; S. Valenti, University of California at Santa Barbara and Las Cumbres Observatory Global Telescope; and N. Elias-Rosa, Institut de Ciencies de L'Espai, CSIC-IEEC, Barcelona) report that optical spectroscopy of PSN J12211796+1130252, obtained on Feb. 14.93 UT with the Asiago 1.82-m Copernico Telescope (+ AFOSC; range 340-820 nm; resolution 1.3 nm) and on Feb. 15.11 with the TNG (+ Dolores; range 320-800 nm; resolution 1.4 nm), shows a blue continuum (T_bb = 15300 K) with superimposed, narrow, unresolved (FWHM < 600 km/s) emission lines of H, [O II], [O III], [N II], and [S II]. However, they cannot disentangle the intrinsic transient contribution to line emissions because of the heavy contamination from nearby H II regions. From the observed wavelength of the H_alpha and H_beta peaks, they derive a redshift, z, around 0.0012, which coincides with that given for the host galaxy, NGC 4294 (Brian et al. 2008, A.J. 136, 713; via NED). The spectra, together with the faint peak absolute magnitude of the transient (about -14; assuming a distance modulus m-M = 31.13, from the Extragalactic Distance Database, Tully et al. 2009, A.J. 138, 323), suggest that PSN J12211796+1130252 is a supernova imposter, likely a major eruption of a luminous blue variable. Long-term photometric monitoring has been activated. The Asiago classification spectra are posted at the following website URL: http://graspa.oapd.inaf.it.