[vsnet-campaign-dn 4566] (fwd) ATEL #652: New eclipsing CV with a short orbital period

[Makoto Uemura]

(fwd) ATEL #652: New eclipsing CV with a short orbital period

The period is 0.06685(2) d, or 96.26 min.  
If the reported magnitude of 17.0mag is a quiescent one, 
we can expect relatively bright superoutbursts. 

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ATEL #652							     ATEL #652

Title:		Discovery of deep eclipses in the cataclysmic variable 1RXS
		J020929.0+283243
Author:	D.V. Denisenko (IKI, Moscow), R.A. Sunyaev (IKI, Moscow; MPA,
		Garching), Z. Aslan (TUG, Antalya), I. Khamitov (TUG, Antalya)
Queries:	sergei at hea.iki.rssi.ru
Posted:	8 Nov 2005;  10:17  UT
Subjects:	Optical, X-ray, Cataclysmic Variables, Variables

In course of the search for optical identifications of bright ROSAT sources
with the 1.5-m Russian-Turkish Telescope RTT150 (Bakyrlytepe, Turkey) we
have discovered very deep (4.5 mag) eclipses of the cataclysmic variable
in the error box of 1RXS J020929.0+283243.  Six eclipses with duration
of about 6 min were observed during the nights of Oct. 22-27, 2005.  The
orbital period is 0.06685(2) d, or 96.26 min.  Light elements are: T =
2453666.543 + 0.06685 * E.   Fine details are present in the  light curve
which are most probably caused by the changing geometry of an accretion
disc. The total range of variations is 17.0-21.5 mag.  We note the marginal
detection of a possible "central flash" event in the middle of eclipses
at JD 2453669.484 and 2453669.551.  This flash can be explained by the
larger companion acting as a lens bending the light of a white dwarf in
the center of an eclipse. Light curve covering two periods between 21:50
UT on Oct. 25 and 01:30 UT on Oct. 26 is available at   http://hea.iki.rssi.ru/~denis/J020929-RTT_LC-051025.gif
Coordinates of the cataclysmic variable measured relative to UCAC2 catalogue
are: RA=02h09m29.82s, Dec=+28o32'29.1" (J2000.0).

We also note the presence of another object of stellar appearance
within the ROSAT error circle 10.1"E and 18.8"N from the CV  (position
end figures 30.59s, 47.9") with a magnitude of 18.5 surrounded by 4 faint
galaxies.  The object is showing variability with an amplitude of 0.3 mag
on the timescale of days.  The color combined chart of the 3'x2.5' region
can be found at   http://hea.iki.rssi.ru/~denis/J020929-RTT_field-color.jpg

Future optical observations are necessary to determine the type of
variability of this CV (UGSU, UGWZ or AM) and to monitor the nearby source.
We also encourage the observations by X-ray telescopes with angular resolution
better than 10" to resolve the structure of the source and to look for
the X-ray eclipses of the CV using the ephemeris provided above.  

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