[vsnet-alert 13871] TCP J06112800+4041087 is likely a new UGWZ variable

Denis Denisenko d.v.denisenko at gmail.com
Sun Nov 20 14:54:00 JST 2011

D. Denisenko (IKI, Moscow), V. Gerke and S. Korotkiy (Ka-Dar
observatory, Russia) report:

We have observed the transient object in Auriga from CBAT TOCP
discovered on 2011 Nov. 18.07 UT by Jan Vales at Crni Vrh observatory
in Slovenia (discovery magnitude 15.8). Our observations were
performed remotely with the 40-cm Djigit telescope + STL-11000M CCD of
Ka-Dar Observatory's TAU Station (Nizhniy Arkhyz, Karachay-Cherkessia,
Russia). Forty 120-sec unfiltered exposures were obtained. Data are
covering 2.0 hours from 22:18 UT on Nov. 19 to 00:16 UT on Nov. 20
with a 12-minute gap at 23:25-23:37 due to meridian crossing. SNR of
the variable on individual images was changing from 95 to 75.

The position of the new variable (average of eight images, each with
600-sec combined exposures) is 06 11 28.00 +40 41 08.8 (J2000.0).

Using R=16.1 for comparison star USNO-A2.0 1275-06016230 (06 11 25.65
+40 41 37.4 R=16.1 B=16.9), we have obtained the light curve of the
new variable. It is showing a likely orbital hump with an amplitude of
0.12m (16.46-16.58) and apparent fading by 0.04m in 2 hours. A very
preliminary analysis of the light curve suggests the likely orbital
period of 1.35 hr (0.056 d). The longer time series are required to
improve the period value.

We have also checked the available archival images of the field (six
Palomar DSS plates and eight NEAT CCD images). Nothing is visible at
the position of new variable neither at any individual image nor at
the sum of them. The limiting magnitude of the combination of all
images is about 22.5m. Comparison of TAU/Ka-Dar and NEAT images is
uploaded at http://pics.livejournal.com/bigdenru/pic/000ay77f

While more data are obviously necessary, one can suggest from the
outburst amplitude (more than 6 magnitudes) and the fast variability
that this transient is likely a new dwarf nova of WZ Sge subtype, i.e.
UGWZ cataclysmic variable.

Denis Denisenko

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