\documentstyle[twoside, epsf]{article}
\input ibvs2.sty

\begin{document}

\IBVShead{5366}{21 January 2003}

\IBVStitletl{Three New W~UM\lowercase{a} Binaries: GSC 0766-1248 (B\lowercase{rh} V40),}{  GSC 0471-2133 (B\lowercase{rh} V60) and GSC 0763-0572 (B\lowercase{rh} V103)}

\IBVSauth{Lloyd, C.$^{1}$; Moschner, W.$^{2,6}$; Kiyota, S.$^{3}$; Bernhard, K.$^{4,6}$; Frank, W.$^{5,6}$}

\IBVSinst{Space Science \& Technology Department, Rutherford Appleton Laboratory, Chilton, Didcot, \\  Oxon.\ OX11 0QX, UK; e-mail: {\tt cl@astro1.bnsc.rl.ac.uk}}
\IBVSinst{D-57368 Lennestadt, Germany; e-mail: {\tt wolfgang.moschner@t-online.de}}
\IBVSinst{1-401-810 Azuma, Tsukuba, 305-0031 Japan; e-mail: {\tt skiyota@nias.affrc.go.jp}}
\IBVSinst{A--4030 Linz, Austria; e-mail: {\tt kl.bernhard@aon.at}}
\IBVSinst{D--84149 Velden, Germany; e-mail: {\tt frank.velden@t-online.de}}
\IBVSinst{Bundesdeutsche Arbeitsge\-mein\-schaft f\"{u}r Ver\"{a}nderliche Sterne e.V. (BAV), Munsterdamm 90,\\ D--12169~Berlin, Germany}

\SIMBADobjAliasJ2000{Brh V40}{GSC 0766-1248}{07 13 34.142 +10 15 12.91}
\SIMBADobjAliasJ2000{Brh V60}{GSC 0471-2133}{19 14 39.648 +03 50 39.85}
\SIMBADobjAliasJ2000{Brh V103}{GSC 0763-0572}{07 16 57.323 +09 12 35.46}

\IBVStyp{ EW }
\IBVSkey{W UMa binaries - variable stars - photometry}

\IBVSabs{The three stars are shown to be W UMa binaries with periods of}
\IBVSabs{1.121968, 0.5878039 and 0.426388 days respectively. GSC 0766-1248}
\IBVSabs{and GSC 0763-0572 both have deep eclipses, about 0.5 mag, and the}
\IBVSabs{secondary eclipses are total. GSC 0471-2133 is a lower inclination}
\IBVSabs{system with an amplitude of 0.35 mag.}

\begintext

Further observations are presented of three new W~UMa systems
recently discovered by Bernhard (2000a, 2000b, 2002). Details
of the observing programme are given by Bernhard \& Lloyd (2000) and an
up-to-date list of the variables can be found at\\
{\tt http://mitglied.lycos.de/klausbernhard/}. Details of the equipment used
are given by Lloyd et al. (2002) and Bernhard et al. (2001).

\begin{table}[!h]\centering
\normalsize
\caption{Brh V40 - Times of minima}
\vskip 2pt
\begin{tabular}{lrcc} \hline
~~~~~~HJD & Cycle & $O-C$ & Min \\ \hline
2451924.4334(11)&$-$24~ &$+$0.0001 & I~ \\
2451951.3609(8) &0~ &$+$0.0004 & I~ \\
2451955.2867(13)&3~ &$-$0.0007 & II \\
2451965.3864(6) &12~ &$+$0.0013 & II \\ \hline
\end{tabular}
\end{table}

\vskip 6pt
Brh V40 = GSC 0766-1248 (07\hr13\mm34\fsec142 +10\deg15\arcm12\farcs91
Tycho-2) was initially reported as a short-period variable by Bernhard
(2000a) on the basis of six nights of survey data. Brh V40 has
$V=11\fmm42\pm0\fmm10$ and $B-V=+0\fmm40\pm0\fmm14$ from the Tycho-2 
catalogue (H\o g et al. 2000), while the USNO A2.0 catalogue gives 
a consistent $r=12\fmm0$
and $b-r=1\fmm0$ (Monet et al. 1998). Further extensive photometry during
2001 and 2002 has confirmed that it is a W~UMa binary with a period of
just over one day. The reference star used was GSC 0766-0142 with
$V=12\fmm11$ (Tycho-2). A total of four minima have been observed which are
given in Table 1. The ephemeris of primary minimum is given by

\[
\begin{array}{r@{}r@{}l}
{\rm HJD}_{\rm MinI} = 2451951.3605 & {} + 1\fday121968 & {} \times E\ .\\
\pm 5 & \pm 6 \\
\end{array}
\]

\IBVSfig{8cm}{5366-f1.eps}{The phase diagram of Brh V40 = GSC 0766-1248.
The observations of Moschner (open circles) and Bernhard (filled circles)
are folded with the ephemeris given in the text.}
%\IBVSfigKey{5366-f1.eps}{GSC 0766-1248}{light curve}

The light curve is given in Figure 1 and shows an amplitude of nearly
0\fmm6. The secondary eclipse is slightly less deep and is probably
total, indicating that the inclination is close to 90\deg. The period is
long for a W~UMa system: it lies in the top $\sim 1$\% of the EW
variables in the GCVS (Kholopov et al. 1998) and these systems are often
not in contact (classified EW/D or /DM) or are referred to as Beta Lyrae
variables (EB/\dots). Typical systems in this group are AT Cam (EW/DM:) and
AZ Cam (EB/DM), which are probably just detached (Zhai et al. 1984).
However, while their amplitudes are similar to that of Brh V40 their
light curve are less sinusoidal, suggesting that Brh V40 is more nearly a
contact system.


\begin{table}[!h]\centering
\normalsize
\caption{Brh V60 - Times of minima}
\vskip 2pt
\begin{tabular}{lrcc} \hline
~~~~~~HJD & Cycle & $O-C$ & Min \\ \hline 
 2451838.2531(14)& $-$1066& $+$0.0003& II \\
 2452464.5607(13)&     0&  $+$0.0028& I~ \\
 2452475.4301(8) &    18&  $-$0.0022& II \\
 2452484.5417(9) &    34& $-$0.0015& I~ \\
 2452489.5412(19)&    42&  $+$0.0016& II \\
 2452556.2575(18)&   156&  $+$0.0022& I~ \\ \hline
\end{tabular}
\end{table}

\IBVSfig{8cm}{5366-f2.eps}{The phase diagram of Brh V60 = GSC 0471-2133.
The observations of Bernhard (open circles) and Frank (filled
circles) are folded with the ephemeris given in the text.}
%\IBVSfigKey{5366-f2.eps}{GSC GSC 0471-2133}{light curve}


Brh V60 = GSC 0471-2133 (19\hr14\mm39\fsec648 +03\deg50\arcm39\farcs85
Tycho-2) was initially reported as a probable short-period variable of
unknown type by Bernhard (2000b). Photometry from Tycho-2 gives
$V=12\fmm0\pm0\fmm2$ and $B-V=-0\fmm2\pm0\fmm3$ while USNO A2.0 gives 
$r=11\fmm6$ and
$b-r=0\fmm8$. Extensive photometry during 2000 and 2002 has shown that it
is a W~UMa system, although the colour suggests that it is probably an
early spectral type. The reference star used was GSC 0471-2309 with
$V=11\fmm67$ (Tycho-2). Six times of minima have been observed and these are
given in Table 2. The ephemeris of primary minimum is given by
\[
\begin{array}{r@{}r@{}l}
{\rm HJD}_{\rm MinI} = 2452464.5579 & {} + 0\fday5878039 & {} \times E\ . \\
\pm 5 & \pm 7 \\
\end{array}
\]

The light curve is given in Figure 2 and shows an amplitude of 0\fmm35, with
both minima reaching almost the same depth. The secondary minimum may be marginally less deep than the primary, and is apparently broader, but the eclipse is probably not total.

\vskip 6pt

\begin{table}[!h]\centering
\normalsize
\caption{Brh V103 - Times of minima}
\vskip 2pt
\begin{tabular}{lrcc} \hline
~~~~~~HJD & Cycle & $O-C$ & Min \\ \hline
2452318.0524(3) &$-$43~~& $-$0.0006 & I~ \\
2452325.0886(2) &$-$27~~& $+$0.0002 & II \\
2452336.3876(4) &0~~& $-$0.0001 & I~ \\
2452361.3321(5) &58~~&$+$0.0007 & II \\
2452362.3974(6) &61~~&$+$0.0000 & I~ \\ \hline
\end{tabular}
\end{table}

Brh V103 = GSC 0763-0572 (07\hr16\mm57\fsec323 +09\deg12\arcm35\farcs46
Tycho-2) was initially reported as a short-period variable by Bernhard
(2002) following several long runs of observations. It has $V=10\fmm61\pm0\fmm06$
and $B-V=+0\fmm64\pm0\fmm09$ from the Tycho-2 catalogue, and $r=10\fmm4$ and
$b-r=1\fmm0$ from the USNO A2.0 catalogue. Further extensive photometry during
2002 has shown that it is W~UMa binary. The reference star used was GSC~0763-0631 with $V=9\fmm82$ (Tycho-2). Five times of minima have been observed and
these are given in Table 3. The ephemeris of primary minimum is given by

\[
\begin{array}{r@{}r@{}l}
{\rm HJD}_{\rm MinI} = 2452336.3877 & {} + 0\fday426388 & {} \times E\ .\\
\pm 4 & \pm 3 \\
\end{array}
\]

The light curve is given in Figure 3 and shows an amplitude of 0\fmm5. The
secondary eclipse is slightly less deep and is probably total, indicating
that the inclination is close to 90\deg. The instrumental $V-I_c$ from
the TASS archive ({\tt http://www.tass-survey.org}) shows a small
variation in colour with the system being coolest during primary minimum.

{\it Acknowledgements.} It is a pleasure the acknowledge the use of the
SIMBAD database, operated by the CDS at Strasbourg, France.


\IBVSfig{9.6cm}{5366-f3.eps}{(Above) The phase diagram of Brh V103 = GSC
0763-0572. The observations of Moschner (open squares), Kiyota (open
circles) and Bernhard (open diamonds) are folded with the ephemeris
given in the text. (Below) The TASS instrumental $V-I_c$ magnitudes.}
%\IBVSfigKey{5366-f3.eps}{GSC 0763-0572}{light curve}


\references

Bernhard, K., 2000a, vsnet-newvar, No. 292\\ 
%%BeV40
{\tt http://www.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-newvar/msg00292.html}

Bernhard, K., 2000a, vsnet-newvar, No. 556\\ 
%%BeV60
{\tt http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-newvar/msg00556.html}

Bernhard, K., 2002, vsnet-newvar, No. 1395\\ 
%%BeV103
{\tt http://www.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-newvar/msg01395.html}

Bernhard, K., Kiyota, S., Lloyd, C., 2001, {\it IBVS}, No.\ 5176 
%%V35

Bernhard, K., Lloyd, C., 2000, {\it IBVS}, No.\ 4920

H\o g, E., Fabricius, C., Makarov, V. V., Urban, S., Corbin, T., Wycoff, G., Bastian, U., Schwekendiek, P., Wicenec, A., 2000, {\it A\&A}, {\bf 355}, L27 
%%Tycho-2

Kholopov, P. N., Samus, N. N., Frolov, M. S., Goranskij, V. P., Gorynya, N. A.,
Karitskaya, E. A., Kazarovets, E. V., Kireeva, N. N., Kukarkina, N. P., Kurochkin, N. E., Medvedeva, G. I., Pastukhova, E. N., Perova, N. B., Rastorguev, A. S., Shugarov, S. Yu., 1998, {\it The Combined General Catalogue of Variable Stars}, 4.1 Edition

Lloyd, C., Frank, P., Bernhard, K., Moschner, W., 2002, {\it IBVS}, No.\ 5260

Monet, D., Bird, A., Canzian, B., Dahn, C., Guetter, H., Harris, H., Henden, A., Levine, S., Luginbuhl, C., Monet, A. K. B., Rhodes, A., Riepe, B., Sell, S.,
Stone, R., Vrba, F., Walker, R., 1998, {\it The USNO-A2.0 Catalogue}

Zhai, D. S., Leung, K. C., Zhang, R. X., Zhang, J. T., 1984, {\it A\&A}, {\bf 141}, 266

\endreferences


\end{document}

