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\IBVShead{5049}{21 March 2001}

\IBVStitle{Two New Contact Binary Stars} 
\IBVSauth{Cs\'ak, B.$^{1}$; Kiss, L.L.$^{2,4}$; Kov\'acs, D.$^{2,4}$; M\'esz\'aros, Sz.$^{2,4}$; S\'arneczky, K.$^{3,4}$;\\ \indent Sz\'ekely, P.$^{2,4}$}

\IBVSinst{Department of Optics \& Quantum Electronics and Astronomical
Observatory, University of Szeged,\\ \indent
P.O. Box 406, H-6701 Hungary, e-mail: csakb@physx.u-szeged.hu}

\IBVSinst{Department of Experimental Physics and Astronomical Observatory,
University of Szeged, Hungary}

\IBVSinst{Department of Physical Geography, ELTE University, Hungary}

\IBVSinst{Guest Observer at the Konkoly Observatory}


\IBVStyp{ EW }

\IBVSkey{CCD photometry}

\IBVSabs{We report the discovery of two new field variable stars based on}
\IBVSabs{CCD observations carried out between October and December, 2000.}
\IBVSabs{Using multicolour photometry we could classify these stars as}
\IBVSabs{W UMa type variables, and we could determine accurate period for each}
\IBVSabs{of them.}

\begintext

When performing the unfiltered photometric CCD observations of the
minor planet (5690) we discovered two new field variable stars in
October, 2000. We made follow-up multicolour observations through
$BVR_{\rm C}$ filters of these stars on four nights in December, 2000.
In this paper we report the results of these observations. The new
variable stars have been named continuing the designation system of
Cs\'ak et al.\ (2000b).

The observations were carried out with the 60/90/180 cm
Schmidt-telescope of the Piszk\'estet\H o Mountain Station of the
Konkoly Observatory. The detector was a Photometrics AT200 CCD camera
(1536$\times$1024 pixels) giving a $29\arcm\times18\arcm$ field of
view. The reduction of the discovery frames was the same as has been
described in Cs\'ak et al.\ (2000a), while in December we made
differential photometry relative to selected local comparison stars GSC
3762-0061 and GSC 3762-0231 (Guide CD-ROM Star Chart, 1997). Individual
data are avaliable at the IBVS website as files 5049-t3.txt (V31) and
5049-t4.txt (V32). 

\IBVSedata{5049-t3.txt} \IBVSedata{5049-t4.txt}

Due to instrumental difficulties we could not transform the
measurements to the standard system, but the light curve shape of the
new variables and the lack of colour variations (constant amplitude in
every band) suggested that these ones are W~UMa type stars. We have
got a relatively good phase coverage for both stars so we could do an
accurate period search for each stars using the Period98 software
(Sperl, 1998). We present the obtained phased light curves in
Figs.~1-2. It is notable that both of primary and secondary minima of
V32 are total eclipses. It means that the inclination of the eclipsing
system should be near to 90 degrees, so -- for example -- the
inclination ambiguity is almost completely exluded from the light curve
modelling and stellar mass determination. The basic data of the new
variables (celestial coordinates, epochs, periods etc.)\ are summarized
in Table~2. We have collected 13 times of minimum of the stars using
low order polynomial fitting for V31 and bisecting chords method for
V32. The obtained times of minimum are collected in Table~1.

\IBVSfig{10cm}{5049-f1.eps}{Unfiltered, $B$, $V$ and $R$ light curves of V31}

\IBVSfig{10cm}{5049-f2.eps}{Unfiltered, $B$, $V$ and $R$ light curves of V32}

\IBVSfig{10cm}{5049-f3.eps}{Finder chart for V31 and V32. The center of the frame is $\alpha(2000)=05\hr58\mm50\fsec0$, $\delta(2000)=+59\deg48\arcm00\farcs0$, North is up, East is to the left}

\begin{table}
\begin{center}
\caption{Times of minimum for V31 and V32}
\vskip 3mm
\begin{tabular} {lcclcc}
\hline
Star & HJD & Type & Star & HJD & Type\\
\hline
V31 & 2451830.4310 & -- & V31 & 2451883.5383 & -- \\
V31 & 2451830.5730 & -- & V32 & 2451880.3732 & \\
V31 & 2451880.3583 & -- & V32 & 2451880.5571 & \\
V31 & 2451880.4936 & -- & V32 & 2451881.2853 & II \\
V31 & 2451881.3242 & -- & V32 & 2451881.4668 & I \\
V31 & 2451881.4662 & -- & V32 & 2451883.4788 & \\
V31 & 2451883.3975 & -- & & & \\
\hline
\end{tabular}
\end{center}

\begin{center}
\caption{Basic data of the new variables. The coordinates were taken from
USNO-A1.0}
\vskip 3mm
\begin{tabular} {lll}
\hline
 & V31 & V32 \\
\hline
R.A. (2000) & 05\hr58\mm15\fsec56 & 05\hr59\mm25\fsec69 \\
Dec.\ (2000) & +59\deg46\arcm22\farcs46 & +59\deg51\arcm23\farcs95 \\
Epoch & 2451830.4310 & 2451881.4668 \\
Period (days) & 0.276593 & 0.365721 \\
$V$ magnitude & 14.5 & 16.0 \\
$V$ amplitude & 0.2 & 0.4 \\
Type & EW & EW \\
\hline
\end{tabular}
\end{center}
\end{table}

\vskip-33pt
{\it Acknowledgements:} This work has been supported by FKFP Grant
0010/2001, OTKA Grant \#T032258,
Pro Renovanda Cultura Hungariae Foundation Grant m\'aj./44, 
and ``Bolyai J\'anos'' Research Scholarship
of LLK from the Hungarian Academy of Sciences.
The warm hospitality of the staff of the Konkoly Observatory
is gratefully acknowledged.
We used the SIMBAD database, operated at CDS, Strasbourg, France.

\references

Cs\'ak, B., Kiss, L.L., Szab\'o, Gy., S\'arneczky, K., Szil\'adi, K., 2000a,
{\it IBVS}, No.\ 4875

Cs\'ak, B., Kiss, L.L., Szil\'adi, K., S\'arneczky, K., Szab\'o, Gy., 2000b,
{\it IBVS}, No.\ 4881 

Guide CD-ROM Star Chart, 1997, Project Pluto, {\tt http://www.projectpluto.com} 

Sperl, M., 1998, {\it Comm.\ Astr.\ Seis.}, No.\ 111 

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