Electronic Telegram No. 2199
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Room 209; Dept. of Earth and Planetary
 Sciences; Harvard University; 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbat@iau.org; cbatiau@eps.harvard.edu
URL http://www.cfa.harvard.edu/iau/cbat.html


V407 CYGNI
     Hiroyuki Maehara, Kwasan Observatory, Kyoto University, reports the
discovery by Koichi Nishiyama (Fukuoka, Japan) and Fujio Kabashima (Saga,
Japan) of an apparent unusually bright outburst (mag 7.4) of the symbiotic
star V407 Cyg on an unfiltered CCD image taken on Mar. 10.797 UT using a
105-mm camera lens (+ SBIG STL6303E camera).  Nishiyama and Kabashima
confirmed the outburst on two unfiltered CCD frames taken on Mar. 10.813 (at
mag 6.8) and 10.814 (mag 6.9) using a 0.40-m reflector (+ SBIG STL1001E
camera); they also report the following pre-outburst magnitudes from
unfiltered CCD images using the 105-mm lens:  2008 Dec. 3.421, 12.4; 2009
Jan. 2.409, 12.5; Jan. 15.406, 12.5; Feb. 14.848, 12.5; Mar. 25.824, 12.0;
Apr. 21.658, 11.2; May 24.736, 11.0; Jun. 25.702, 11.0; Aug. 7.572, 11.1;
Sep. 3.667, 11.3; Oct. 3.548, 10.6; Nov. 3.465, 9.6; Dec. 3.428, 9.2;
2010 Jan. 3.413, 9.2; Jan. 17.409, 9.3; Feb. 22.834, 9.6; Feb. 23.817;
Mar. 7.859, 9.8.  Maehara adds that CCD images taken with a 25-cm telescope
of the Kwasan Observatory yields following magnitudes:  Mar. 11.8524, I_c =
5.31; 11.8525, R_c = 6.68; 11.8527, V = 7.94; 11.8531, B = 8.97.  Maehara
also forwards the following visual magnitude estimates:  Mar. 11.836, 7.4
(K. Hirosawa, Aichi, Japan); 11.864, 7.9 (Maehara).
     S. Nakano, Sumoto, Japan, reports the apparent independent discovery
of this outburst by Tadashi Kojima (Tsumagoi, Agatsuma-gun, Gunma-ken, Japan),
who reported it as a possible nova of mag about 7 on two frames taken on
Mar. 11.789 UT using a Canon EOS 40D Digital Camera (+ 50-mm f/2.8 camera
lens mounted on a Sky-Memo equatorial instrument).  Nakano has measured the
following position for the variable from Kojima's JPEG image (limiting mag
12.2), upon which the variable is at mag 7.3:  R.A. = 21h02m10s.18, Decl. =
+45o46'30".8 (equinox 2000.0; uncertainty about 8").  Kojima writes that
nothing is visible at this position on his survey frames taken on 2010 Jan.
29 (limiting mag 11), Feb. 23, and 24 (limiting mag 12).
     The General Catalogue of Variable Stars lists the position of V407 Cyg
as R.A. = 21h02m09s.9, Decl. = +45o46'33" (equinox 2000.0), noting its
observed range to be magnitude 13 to fainter than 17; it may have been a
slow nova in 1936, and a Mira-type variable appears involved with this
object, as well.  Additional spectroscopy is urged to determine the
nature of this object, as well as more accurate astrometry.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2010 CBAT
2010 March 12                    (CBET 2199)              Daniel W. E. Green