[vsnet-alert 8893] New eclipsing variable (possible CV) in Lacerta

[Denis Denisenko]

T.Kryachko (StarLab observatory), S.Korotkiy (Scientific Centre Ka-Dar, 
Russia) report on the serendipitous discovery of the eclipsing variable 
in Lacerta during their CCD-observations of comet C/2006 A1 Pojmanski 
with 80-mm refractor on Kazan station, Karachay-Cherkessiya.  Thirty 
5-minute exposures were taken from 2006 Mar. 28, 23:07 UT to Mar. 29, 
01:40 UT using 80/600mm Skywatcher 80ED + CCD SBIG 2000XM.  During the 
visual blinking of images the variable star with an amplitude of 
variations about 3 magnitudes was found by Timur Kryachko at the 
following position:

RA = 22 16 50.301, Dec = +46 46 41.30 (J2000.0)

Astrometry was performed by Stanislav Korotkiy with IzmCCD software.
The star with the following ID, coordinates, Red and Blue magnitudes  is 
present in USNO-A2.0 catalogue:
U1350_16249624  22 16 50.38 +46 46 41.8  15.5  15.3

The (unfiltered) photometry below was made by S.Korotkiy using TYC 
3606-02008-1 with BT=10.36, VT=10.08 as comparison star:

Mid-exposure time
UT, 28/29.03.2006
hh mm ss    V
23:09:32  16.29
23:14:39  17.29
23:19:46 >17.5
23:24:53  17.5
23:30:00  16.69
23:35:07  15.93
23:40:14  15.68
23:45:20  15.87
23:50:27  15.47
23:55:35  15.18
00:00:41  15.06
00:05:48  15.05
00:10:55  15.07
00:16:02  14.85
00:21:10  14.90
00:26:17  14.69
00:31:24  15.15
00:36:31  14.91
00:41:38  14.87
00:46:45  14.61
00:51:52  14.55
00:56:59  15.01
01:02:06  14.68
01:07:13  14.97
01:12:21  14.66
01:17:28  14.69
01:22:35  14.72
01:27:42  14.73
01:32:49  14.88
01:37:56  14.90

Light curve is available online at:
http://www.starlab.ru/forum/album_pic.php?pic_id=1225

DSS finder chart with the position of variable marked with an arrow:
http://www.starlab.ru/forum/album_pic.php?pic_id=1227

The position of the variable is coincident with the emission-line star 
HBHA 4705-03 (Kohoutek, Wehmeyer, 1997) of 15.1 visual magnitude.  We 
also note the presence of the faint X-ray source 1RXS J221653.0+464804 
about 1.5' North of the variable star.

Observations are continuing to determine the orbital period of binary 
system which is more than 2 hours.  Since the object is currently 
visible in the morning hours only from the northern hemisphere, 
follow-up from other longitudes is encouraged.

Denis
--
Denis V. Denisenko
Space Research Institute
Profsoyuznaya st., 84/32
117997, Moscow, Russia
denis at hea.iki.rssi.ru