Electronic Telegram No. 3724 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 NOVA SERPENTIS 2013 = PNV J18090346-1112345 Syuichi Nakano, Sumoto, Japan, reported the discovery by Koichi Itagaki (Teppo-cho, Yamagata, Japan) of a possible nova (mag 12.3) on an unfiltered CCD frame (limiting magnitude about 15) taken on Nov. 24.384 UT using a 0.21-m f/3 reflector, confirmed on frames taken with a 0.50-m f/6 reflector; the new object is located at R.A. = 18h09m03s.46, Decl. = -11d12'34".5 (equinox 2000.0). Nothing is visible at this position on Itagaki's survey frame taken on Nov. 6.375 (limiting mag about 15). Itagaki has posted his discovery image at website URL http://www.k-itagaki.jp/images/Ser.jpg. The variable was designated PNV J18090346-1112345 when it was posted at the Central Bureau's TOCP webpage. Additional CCD magnitudes for the variable, all communicated by Nakano: Nov. 22.370 and 23.361, [13 (Tadashi Kojima, Tsumagoi, Gunma-ken, Japan; 150-mm f/2.8 lens + Canon EOS 60D digital camera); 26.369, 11.7 (Itagaki; 0.50-m f/6.8 reflector remotely at Takanezawa; position end figures 03s.42, 34".7; image posted at http://www.k-itagaki.jp/images/ser-2.jpg); 26.373, 12.7 (T. Kojima, Gunma-ken, Japan; 150-mm f/2.8 lens + Canon EOS 60D camera). Patrick Schmeer, Bischmisheim, Germany, notes that an apparent star catalogued as UGPS J180903.43-111234.3 in the UKIDSS-DR6 Galactic Plane Survey (Lucas et al. 2012) has position end figures 03s.433, 34".39 and H magnitude 20.9. Ulisse Munari, Astronomical Observatory of Padova, INAF; and Paolo Valisa, ANS Collaboration, report that a low-resolution spectrogram (range 390-860 nm, 0.21 nm/pixel) of PNV J18090346-1112345 was obtained on Nov. 25.792 UT with the Varese 0.61-m telescope (+ Multi-Mode spectrograph). The spectrum has a low signal-to-noise ratio because the target was only briefly observable very low on the horizon after sunset. The spectrum is clearly that of a nova with hydrogen Balmer lines and O I 777.2-nm, 844.6-nm in emission. The FWHM of H_alpha is 1100 km/s, and the H_alpha/H_beta flux ratio is 25. The O I 844.6-nm/777.2-nm flux ratio is 2.0. A P-Cyg absorption component is visible in O I 777.2-nm, blue-shifted by 1400 km/s with respect to the emission component. The slope of the continuum corresponds to a photometric color of B-V = +0.6. R. Itoh, Y. Kanda, Y. Moritani, and K. S. Kawabata, Hiroshima University, obtained a low-resolution optical spectrogram (range 400-950 nm) of PNV J18090346-1112345 on Nov. 25.37 UT with the 1.5-m Kanata telescope (+ HOWPol) at Higashi-Hiroshima Observatory. The spectrum is consistent with a reddened, post-maximum classical nova. It shows strong emission lines of Balmer series as well as O I 777.3-nm and the Ca II infrared triplet. The H-alpha line has an equivalent width of about -37 nm and a FWHM of about 900 km/s, and no significant absorption component is seen with the Balmer lines. On the other hand, a weak, blue-shifted absorption component (-1400 km/s) is associated with the O I 777.3-nm emission line. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2013 CBAT 2013 November 28 (CBET 3724) Daniel W. E. Green