Electronic Telegram No. 2903 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@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network SUPERNOVA 2011ht IN UGC 5460 = PSN J10081059+5150570 J. L. Prieto, Princeton University; R. McMillan, New Mexico State University; and G. Bakos, Princeton University, report that they obtained an optical spectrum (range 350-960 nm; resolution 0.7 nm) of PSN J10081059+5150570 (cf. CBET 2851) with the APO 3.5-m telescope (+ DIS) on Nov. 11.5 UT. The spectrum shows substantial evolution with respect to the initial classification spectrum reported by Pastorello et al. It has a blue continuum with strong Balmer lines and weaker He I and Fe II lines in emission. The H-alpha line profile is asymmetric and can be relatively well-fitted using two Gaussian components with FWHM = 1300 km/s and 5400 km/s. The Balmer lines also show a narrow P-Cyg absorption through on top of the broader profiles, with the minimum at -700 km/s with respect to the central wavelength at rest (obtained after correcting for the recession velocity of the host galaxy, UGC 5460, of 1093 km/s from de Vaucouleurs et al. 1991, RC3 catalogue, via NED). These emission-line profiles are characteristic of the spectra of some type-IIn supernovae (e.g., Kiewe et al. 2010, http://lanl.arxiv.org/abs/1010.2689). This classification is consistent with the current absolute magnitude of the object of M_V = -17 (approximately 2.5 mag brighter than at discovery; Prieto et al. 2011, http://www.astronomerstelegram.org/?read=3749), which is too luminous compared with supernova impostors (e.g., Smith et al. 2011, MNRAS 415, 773). Note also that the blue continuum observed in the spectrum is consistent with the unusual ultraviolet brightening detected in Swift UVOT follow-up observations (as communicated by Roming et al. at website URL http://www.astronomerstelegram.org/?read=3690 and by Prieto et al., loc.cit.). D. Grennan, Dublin, Ireland, reports that PSN J10081058+5150576 = SN 2011ht appeared at mag approximately 14.5 on unfiltered CCD images taken on Nov. 6.05 UT with a 0.35-m Schmidt-Cassegrain telescope (+ SBIG ST8 camera); his image is posted at website URL http://www.webtreatz.com/images/U5460.jpg. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 November 17 (CBET 2903) Daniel W. E. Green