Electronic Telegram No. 2582 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 APPARENT NOVA IN M31: M31N 2010-12b Several independent reports of a discovery of an apparent nova in M31 -- designated M31N 2010-12b -- have been received, as detailed below. M. Koishikawa, Sendai Astronomical Observatory, reports that he found the new object on a CCD image taken with a 1.3-m f/4.85 reflector on Dec. 10.532 UT. W. Pietsch, M. Henze, and V. Burwitz, Max-Planck-Institut fuer Extraterrestrische Physik); A. Kaur and D. H. Hartmann, Clemson University; and P. Milne and G. Williams, University of Arizona, report the discovery of M31N 2010-12b on twelve stacked, 60-s R-band CCD images obtained with the robotic 60-cm telescope (+ E2V CCD camera) of the Livermore Optical Transient Imaging System (Super-LOTIS), located at Steward Observatory on Kitt Peak, on Dec. 11.095 UT; they measure the new object to be 149" west and 672" north of the center of M31. Koichi Nishiyama (Kurume, Japan) and Fujio Kabashima (Miyaki, Japan) report their discovery of M31N 2010-12b on ten 40-s unfiltered CCD frames (limiting magnitude 19.8) taken around Dec. 11.468 UT using a Meade 200R 0.40-m f/9.8 reflector (+ SBIG STL1001E camera). The new object is lcated 149" west and 672" north of the center of the galaxy M31. Guoyou Sun (Wenzhou, Zhejiang, China) and Xing Gao (Urumqi, Xinjiang, China) report their discovery of M31N 2010-12b at mag approximately 17.7 on several unfiltered 60-s survey CCD images (limiting mag about 19.0) taken by Xing Gao in the course of the Xingming Observatory Sky Survey at Mt. Nanshan around Dec. 11.517 UT using a Celestron C14 0.36-m f/6.9 Schmidt-Cassegrain telescope. Gao found a pre-discovery from Dec. 10.515. T. Yusa, Osaki, Japan, also reports a pre-discovery unfiltered CCD image (from twelve co-added 90-s images; limiting magnitude 19.0) of M31N 2010-12b on Dec. 10.359 using a 0.30-m f/7 Cassegrain telescope (+ SBIG STL-1001E) at the Osaki Lifelong Learning Center. Yusa's image is posted at the following website URL: http://space.geocities.jp/yusastar77/PNinM31_101210.htm. Precise astrometric data for M31N 2010-12b are tabulated below: 2010 UT R.A. (2000.0) Decl. Mag. Observers Dec. 10.359 0 42 31.07 +41 27 20.0 16.7 Yusa Dec. 10.515 0 42 31.07 +41 27 20.4 16.1 Gao Dec. 10.532 0 42 30.88 +41 27 21.7 16.0 Koishikawa Dec. 11.095 0 42 31.08 +41 27 20.3 16.6 Pietsch et al. Dec. 11.468 0 42 31.06 +41 27 20.5 17.4 Nishiyama, Kabashima Dec. 11.517 0 42 31.07 +41 27 20.4 17.7 Gao Additional limiting magnitudes for M31N 2010-12b: 1986 Nov. 27, [18.9 (Digitized Sky Survey; red plate; via Nishiyama and Kabashima); 1988 Nov. 27, [20.8 (DSS; red plate; via Sun and Gao); 1993 Oct. 21, [18.5 (DSS; infrared plate via Nishiyama and Kabashima); 2010 Dec. 5.213 UT, [19.0 (Pietsch et al.; R-band); 5.460, [20.0 (Nishiyama and Kabashima); 6.52, [19.0 (Sun and Gao); 8.376, [19.0 (Yusa); 8.508, [19 (Koishikawa); 9.464, [19.9 (Nishiyama and Kabashima). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 December 12 (CBET 2582) Daniel W. E. Green