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\IBVShead{5006}{20 December 2000}
\IBVStitle{UBV Photometry of BX A\lowercase{nd}}
\IBVSauth{Jassur, D.M.Z.; Khalaj, A.; Kermani, M.H.}
\IBVSinsto{Center for Applied Physics and Astronomical Research, Faculty of Physics, Tabriz University, Tabriz, Iran\\ \indent email: Jassur@ark.Tabrizu.ac.ir}

\SIMBADobj{BX And}

\begintext

The short period eclipsing binary BX And (BD\,+40\deg442) is the
brighter component of visual binary ADS 1671 and was discovered as an
Algol type eclipsing binary by Soloviev (1945). Photographic studies by
Ashbrook (1951) using 200 Harvard patrol plates confirmed the binary
nature of BX And with a $\beta$ Lyrae type light variation. Since then,
the system has been observed frequently by many observers (see Rovithis
et al.\ 1984, and Bell et al.\ 1990). G\"ulmen et al.\ (1988)
published a period analysis, summarising the time of minima observed by
many authors. Their analysis confirmed the occurrence of a period
change about 0\fsec25 already reported by Ahnert (1975) and suggested
another change around 1981.

The system consists of a primary with spectral type F2V and a K type
secondary. It has been classified as a near contact binary by Bell et
al.\ (1990). To study the light curve variation, it has been included
in our observing program. $UBV$ photoelectric observations of BX And
were made in October 1996, 1997, 1998 and 2000, at Khajheh Nassir Addin
Observatory of Tabriz University (Iran). The observations were carried
out using a 40-cm Cassegrain telescope. A single channel photometer
equipped with an unrefrigerated photomultiplier tube RCA 1P21 and
Johnson's standard $UBV$ filters were employed during the
observations. The output of the photometer was fed to a microcomputer
enabling rapid data access. Two stars BD\,+39\deg476 and
BD\,+39\deg480 were used as comparison and check stars, respectively.
The data were corrected for differential extinction and light time
effect.
%\IBVSindexobj{BD +39 476}
%\IBVSindexobj{BD +39 480}

The phases were calculated using the elements given by Derman et al.\ (1993):
$${\rm Hel.~JD(Min~I)} = 2447538.2967 + 0\fday61011355 \times E.$$
During the observations three primary and three secondary minimum times
were obtained in each color. These minima are given in Table 1 where
$O-C$ residuals have been computed with the elements given above.
Figures~1 and~2 show the light curves of BX And in $U$, $B$ and $V$ bands
where $\Delta m = {\rm Var.-Comp.}$ have been plotted versus phase. There is no
asymmetry in the profiles of the minima and no displacement in the secondary minimum,
and the maxima are equal.

\IBVSfig{10cm}{5006-f1.eps}{1998 light curves of BX And}
\IBVSfig{10cm}{5006-f2.eps}{2000 light curves of BX And}

\newpage

\begin{table} 
\caption{Time of minima of BX And}
\begin{center}
\begin{tabular}{ccclc}
\hline
Hel.\ JD & \lower6pt\hbox{Filter} & \lower6pt\hbox{$O-C$} & \lower6pt\hbox{Remark} & $O-C$ (average \\[-3pt]
2450000\,+ & & & & of three filters) \\
\hline
 0392.4069 & $U$ & $-0.0007$ & Min I & \\
 0392.4045 & $B$ & $-0.0033$ & Min I & $-0.0019$ \\
 0392.4030 & $V$ & $-0.0048$ & Min I & \\[4pt]
 0731.3224 & $U$ & $-0.0034$ & Min II & \\
 0731.3220 & $B$ & $-0.0039$ & Min II & $-0.0028$ \\
 0731.3258 & $V$ & $-0.0001$ & Min II & \\[4pt]
 1105.3228 & $U$ & $-0.0027$ & Min II & \\
 1105.3214 & $B$ & $-0.0039$ & Min II & $-0.0033$ \\
 1105.3221 & $V$ & $-0.0034$ & Min II & \\[4pt]
 1109.2954 & $U$ & $-0.0012$ & Min I & \\
 1109.2950 & $B$ & $-0.0037$ & Min I & $-0.0025$ \\
 1109.2940 & $V$ & $-0.0027$ & Min I & \\[4pt]
 1823.7294 & $U$ & $-0.0047$ & Min II & \\
 1823.7251 & $B$ & $-0.0090$ & Min II & $-0.0046$ \\
 1823.7338 & $V$ & $-0.0003$ & Min II & \\[4pt]
 1824.9516 & $U$ & $-0.0028$ & Min I & \\
 1824.9516 & $B$ & $-0.0028$ & Min I & $-0.0027$ \\
 1824.9518 & $V$ & $-0.0026$ & Min I & \\
\hline
\end{tabular}
\end{center}
\end{table}

\references

Ahnert, P., 1975, {\it Mitteilungen \"uber Ver\"anderliche Sterne}, {\bf 6}, 189

Ashbrook, J., 1951, {\it Astron.\ J.}, {\bf 56}, 54

Bell, S.A., Rainger, P.P., Hilditch, R.W., Hill, G., 1990, {\it Monthly 
Not.\ Roy.\ Astr.\ Soc.}, {\bf 244}, 328

Derman, E., Demircan, O., and Akalin, A., 1993, {\it Astrophysics and Space 
Sci.}, {\bf 205}, 327

G\"ulmen, O., G\"ud\"ur, N., Sezer, C., Eker, Z., Keskin, V., and Kilinc, B., 1988, {\it IBVS}, No.\ 3266

Rovithis, P., Rovithis-Livaniou, H., 1984, {\it Astrophysics and Space Sci.}, {\bf 105}, 171

Soloviev, A., 1945, {\it Astron.\ Circ.\ Acad.\ USSR}, No.\ 44
 
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