Electronic Telegram No. 1971 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html NOVAE IN M31: 2009-10b AND 2009-10c P. Podigachoski, M. Henze, W. Pietsch, and V. Burwitz, Max-Planck- Institut fuer Extraterrestrische Physik (MPE); G. Papamastorakis and P. Reig, FORTH and Department of Physics, University of Crete; and A. Strigachev, Institute of Astronomy, Bulgarian Academy of Sciences, report the discovery of an apparent nova, designated M31N 2009-10c, very close to the core of M31 on three consecutive dithered stacked CCD images (limiting magnitude 18.5) obtained on Oct. 9.08 UT with the 1.3-m Ritchey-Chretien f/7.5 telescope at Skinakas Observatory (Crete, Greece) using an Andor DZ436-BV CCD Camera (with a Marconi 2000x2000 chip with 13.5-micron-square pixels) and a broad (7.5-nm) H-alpha filter. The new object is clearly visible on the three individual images and one additional image taken at Oct. 9.12 at magnitude 17.2 (photometric solution using R magnitudes of the Local Group Survey M31 catalogue of Massey et al. 2006, A.J. 131, 2478). The nova is located at R.A. = 0h42m45s.76, Decl. = +41o15'57".1 (equinox 2000.0; uncertainty 0".3), which is 16" east and 12" south of the nucleus of M31. No object is visible at this position on an H-alpha image obtained with the same telescope and camera on Aug. 30.07 (limiting magnitude 18.5). K. Hornoch, Ondrejov Observatory, reports that he measured postion end figures 45s.66, 57".3 and magnitude 17.7 for 2009-10c from a co-added 2400-s R-band CCD frame taken by P. Kusnirak with the 0.65-m telescope at Ondrejov on Oct. 9.986 UT. S. Fabrika, O. Sholukhova, and A. Valeev, Special Astrophysical Observatory; K. Hornoch and P. Kusnirak, Astronomical Institute, Ondrejov, Czech Republic; and W. Pietsch, MPE, obtained low-resolution spectra of 2009-10c on Oct. 9.820 UT with the Russian BTA 6-m telescope (+ SCORPIO spectral camera); spectral range 374-783 nm, resolution 1.25 nm). The nova was at magnitudes R = 17.50 +/- 0.08, V = 17.69 +/- 0.07, and B = 18.06 +/- 0.04 on Oct. 9.806. M31N 2009-10c shows a spectrum like that of the Fe II group of novae with hydrogen and many Fe II emission lines. These lines, as well as Na I D1 and D2, are narrow with P-Cyg absorption components. Ca II H and K lines show only blueshifted absorption components. The spectrum is contaminated by strong background of the core of M31. Equivalent widths of H-beta and H-alpha lines are 3.6 and 13.5 nm; their widths (corrected for spectral resolution) are FWHM = 630 and 600 km/s, respectively. The full-width-at-zero-intensity in H-alpha is 1600 km/s. The heliocentric radial velocity of the H-alpha, H-beta, and Fe II 501.8-nm lines is -530 +/- 15 km/s. The blueshifted absorption components have velocities of -1880 km/s in H-beta, -1180 km/s in Fe II 492.3-nm, -1300 km/s in Fe II 501.8-nm, and -1250 km/s in Ca II K. Hornoch also reports his independent discovery, with P. Kusnirak, of the apparent nova 2009-10b announced on CBET 1967, from a co-added 2400-s R-band CCD frame taken by Kusnirak with the 0.65-m telescope at Ondrejov on Oct. 9.986 UT. The new object is marginally visible on single 60-sec images used for the co-added image, but it is not present on numerous archive images taken at Lelekovice and Ondrejov back to 2002. Hornoch provides the following position for 2009-10b: R.A. = 0h42m20s.85, Decl. = +41o16'44".3 (equinox 2000.0), which is 265" west and 36" north of the center of M31. Available R-band magnitudes for 2009-10b: June 3.474, [20.2 (O. Pejcha, 1.3-m telescope at MDM Observatory); 6.027, [20.0 (K. Hornoch, 0.65-m telescope at Ondrejov); Sept. 30.762, [19.9 (P. Kusnirak, 0.65-m telescope at Ondrejov); Oct. 9.986, 18.8 (Kusnirak). Nothing visible at this position on numerous Lelekovice and Ondrejov images back to 2002. S. Nakano, Sumoto, Japan, reports that K. Itagaki finds a further brightening of 2009-10b to unfiltered CCD mag 16.4 on Oct. 12.519 UT. J. Nicolas, Vallauris, France, reports red mag 17.0 and position end figures 20s.84, 44".4 on Oct. 11.965 (0.28-m f/6.5 reflector + CCD). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 October 12 (CBET 1971) Daniel W. E. Green