\documentstyle[twoside,epsf]{article}

\input ibvs2.sty
\input ibvst.sty

\begin{document}

\IBVShead{5294}{20 June 2002}

\IBVStitle{UBVR photometry of the eclipsing binary star V443~Cygni}

\IBVSauth{Eshankulova, M.$^1$; Zakirov, M.$^2$}

\IBVSinst{Astronomical Institut of Uzbek Academy of Sciences,
Astronomicheskaya Ul., 33, Tashkent, 7000052, Uzbekistan, e-mail: manzura@astrin.uzsci.net}

\IBVSinst{Department of Physics, National University of
Uzbekistan, Vuzgorodok, Tashkent, 700174, Uzbekistan, e-mail: astro@nuuz.uzsci.net}


\SIMBADobj{V443 Cyg} 


\begintext


\IBVSTnam{V443 Cyg = AN 540.1936 = GSC 03152-1283 = P5411}

\IBVSTcoo{20\hr 27\mm 45\sec}{+38\deg 41\arcm 24\arcs}{2000.0}

\IBVSTobs{ Maidanak Observatory of Astronomical Institute of Uzbek
Academy of Sciences, 0.6-m Cassegrain telescope.}

\IBVSTdet{ Single channel photometer.}

\IBVSTfil{$UBVR_{J}$}

\IBVSTdateobs{2000.07.23 - 2000.08.26; 2001.07.13 - 2001.08.22.}

\IBVSTcomp{ SAO 70055 = BD +38\deg 4098 = GSC  03152-0050721}

\IBVSTchk{SAO 70047 = BD +38\deg 4092 = GSC  03152-0025322}

\IBVSTsys{Yes}{SA 113 (Landolt,1983)}

\IBVSTdata{Upon request}

\IBVSTtyp{ EA }


V443 Cyg was discovered to be variable  by Hoffmeister (1936). It
was classified as a short period eclipsing star with
0\fday83110 period and light changes between
12.3$-$12.9~pg (Richter, 1958; Schewick, 1941). We have been monitoring the
binary for a total of 45~nights from July to August in 2000 and
2001. Table 1 lists the standard V magnitude and color indices of
field stars near the variable. The photometric values have been
determined  by our  measurements  of the standards in the SA 113
(Landolt, 1983). We have found the following moments of primary
minimum: HJD~2451774.5032~$\pm$~0.0049, 2452115.2329~$\pm$~0.0040.
The analysis of light curves proved that the period of the binary
is twice longer than initially determined. Using 53
moments of minima published in the literature and our
determinations (Table 2 for primary minima, Table 3 for secondary
ones), the following new ephemeris for V433 Cyg was yielded:

\bigskip

\begin{center}
{Min I = HJD2452115.2316 + 1\fday66220545 $\times$ E}\\
\textbf~~~~~~~~~~~~~~~~~$\pm $ 0.0038 $\pm $ 0.00000043
\end{center}

\smallskip

\begin{center}
\centerline{Table 1}
\medskip
\begin{tabular}{|c|c|c|c|c|c|}
\hline
  Star        &          $V$       &     $U-B$         &       $B-V$     &     $V-R$              & Sp\\
\hline
 Comparison(s)& 8.915$\pm $0.011 &0.462 $\pm $0.024 &0.900$\pm $0.014  & 0.551$\pm $0.006 &B91b
 \\
\hline
 Check(s)     & 8.436$\pm $0.004 &1.048 $\pm $0.006 &1.124$\pm $0.002  &0.850 $\pm $0.003 &K2\\
\hline
\end{tabular}
\normalsize
\end{center}

\begin{table}[!h]
\begin{center}
\centerline{Table 2}
\medskip
\small
\begin{tabular}{|c|c|c|c|} \hline
\  Observer        & HJD 2400000+&      E    &   $O - C$   \\ \hline
 \   Richter (1958)& 26206.465   &   $-$15587  &   0.027  \\
 \  Schewick (1941)& 27298.497   &   $-$14930  &  $-$0.007  \\
 \   Richter (1958)& 27298.500   &   $-$14930  &  $-$0.004  \\
 \  Schewick (1941)& 27313.464   &   $-$14921  &  $-$0.000  \\
 \   Richter (1958)& 27313.467   &  $-$14921   &   0.002  \\
 \                 & 28435.434   &  $-$14246   &  $-$0.018  \\
 \                 & 28819.424   &   $-$14015  &   0.002  \\
 \                 & 30375.253   &   $-$13079  &   0.006  \\
 \                 & 31703.363   &   $-$12280  &   0.014  \\
 \                 & 32775.456   &   $-$11635  &  $-$0.015  \\
 \                 & 33204.308   &   $-$11377  &  $-$0.012  \\
 \                 & 33887.457   &   $-$10966  &  $-$0.029  \\
 \                 & 35275.449   &   $-$10131  &   0.020  \\
 \                 & 35629.479   &    $-$9918  &   0.001  \\
 \   Romano (1969) & 36751.500   &   $-$9243   &   0.033  \\
 \                 & 37130.430   &    $-$9015  &  $-$0.019  \\
 \                 & 37190.320   &   $-$8979   &   0.031  \\
 \                 & 37848.507   &   $-$8583   &  $-$0.015  \\
 \                 & 39788.292   &   $-$7416   &  $-$0.024  \\
 \                 & 40117.429   &    $-$7218  &  $-$0.004  \\
 \ Borovicka (1992)& 47670.496   &    $-$2674  &   0.002  \\
 \ Dedoch  (1992)  & 47670.501   &    $-$2674  &   0.007  \\
 \ Zejda et al. (1995)& 48222.346   &    $-$2342  & 0.000  \\
 \                 & 48222.351   &   $-$2342   &   0.004  \\
 \                 & 49171.452   &    $-$1771  &  $-$0.013  \\
 \                 & 49171.460   &   $-$1771   &  $-$0.005  \\
 \                 & 49171.468   &   $-$1771   &   0.002  \\
 \                 & 49181.433   &    $-$1765  &  $-$0.006  \\
 \                 & 49186.418   &   $-$1762   &  $-$0.007  \\
 \                 & 49186.420   &   $-$1762   &  $-$0.005  \\
 \                 & 49186.425   &   $-$1762   &  $-$0.000  \\
 \                 & 49186.426   &   $-$1762   &   0.000  \\
 \                 & 49186.426   &   $-$1762   &   0.000  \\
 \                 & 49595.350   &   $-$1516   &   0.022  \\
 \ Diethelm  (1995) & 49919.457  &   $-$1321   &  $-$0.000  \\
 \ This paper     & 51774.503(5)  & $-$205      &   0.023  \\
 \                 & 52115.233(4)  &  0        &   0.001  \\
\hline
\end{tabular}
\end{center}
\end{table}

\begin{table}
\begin{center}
\centerline{Table 3}
\medskip
\begin{tabular}{|c|c|c|c|} \hline
\  Observer        & HJD 2400000+&     E      &  $O - C$ \\ \hline
 \ Schewick (1941) & 25841.571   &  $-$15806.5  &   $-$0.010   \\
 \ Richter (1958)  & 29488.456   &  $-$13612.5  &   $-$0.004   \\
 \                 & 35369.359   &  $-$10074.5  &    0.016   \\
 \                 & 36072.453   &  $-$9651.5   &   $-$0.003   \\
 \                 & 36127.322   &  $-$9618.5   &    0.013   \\
 \                 & 36137.293   &  $-$9612.5   &    0.011   \\
 \ Romano (1969)   & 37149.543   &  $-$9003.5   &   $-$0.022   \\
 \                 & 37174.522   &  $-$8988.5   &    0.024   \\
 \                 & 37224.385   &  $-$8958.5   &    0.021   \\
 \                 & 37523.504   &  $-$8778.5   &   $-$0.057   \\
 \                 & 39699.373   &  $-$7469.5   &   $-$0.015   \\
 \                 & 40053.426   &  $-$7256.5   &   $-$0.011   \\
 \ Zejda et al. (1995) & 49599.483&  $-$1513.5   &   $-$0.000   \\
 \ Safar, Zejda (2000a)& 50234.446& $-$1131.5   &    0.000   \\
 \ Dedoch (1997)    & 50583.499   &  $-$921.5   &   $-$0.010   \\
 \ Safar, Zejda (2000b)&50947.5353&  $-$702.5   &    0.003   \\
\hline
\end{tabular}
\end{center}
\end{table}

\bigskip

The phased U,B,V,R light curves are presented in Figure 1. 
The depth of the primary and secondary minima are 0\fmm65 and 0\fmm46, 
respectively. Table 4 represents photometric values for
main phases of the binary's light curves. The brightness levels at the
first and second quadratures are slightly different.
\bigskip

\begin{center}
\centerline{Table 4}
\medskip
\begin{tabular}{|c|c|c|c|c|}
\hline
  Ph    &    $V$   &  $U-B$ &  $B-V$ &  $V-R$ \\
\hline
  Max.   & 12.30 & 0.05 & 0.57 & 0.46 \\
\hline
  Min.~I  & 12.95 & 0.01 & 0.66 & 0.50\\
\hline
  Min.~II & 12.76 & 0.05 & 0.51 & 0.45 \\\hline
\end{tabular}
\end{center}

\IBVSTack{During this study we have made use of the Astronomical Data Centre SIMBAD (Strasbourg, France)}


\newpage

\IBVSfig{13cm}{5294-f1.eps}{The phased U,B,V,R light curves.}

\references

Borovicka, J., 1992, {\it Contr. Obs. Planet. Brno}, {\bf No. 30}, 13

Dedoch, A., 1992, {\it Contr. Obs. Planet. Brno}, {\bf No. 30}, 13

Dedoch, A., 1997, {\it BBSAG  Bull.}, {\bf 115}, 6

Diethelm, R., 1995, {\it BBSAG  Bull.}, {\bf 109}, 5

Hoffmeister, C., 1936, {\it AN}, {\bf 259}, 37

Landolt, A.E., 1983, {\it AJ}, {\bf 88}, 439

Richter, G., 1958, {\it MVS}, {\bf 352}

Romano, G., 1969, {\it Mem. Soc. Astr. Ital.}, {\bf 40}, 375

Schewick, H. van, 1941, {\it KVBB}, {\bf No. 24}, 86

Safar, J., Zejda, M., 2000a, {\it IBVS}, No. 4887

Safar, J., Zejda, M., 2000b, {\it IBVS}, No. 4888

Zejda, M. et al., 1995, {\it Contr. Obs. Planet. Brno}, {\bf No. 31}, 22


\endreferences


\end{document}
