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\begin{document}
\IBVShead{4287}{12 January 1996}

\title{NSV\,10183 IS A NEW CEPHEID VARIABLE STAR}

\begintext


NSV\,10183 (S\,9291; GSC\,1008.1699,
$\alpha$ = 18\fh 05\fmm 28\fss 95, $\delta$ = +7\degr 54\farcmm 21\farcs 1, Epoch 2000)
was discovered by Hoffmeister (1966) and classified by him as a
possible eclipsing variable with a short period and an amplitude of about
0.5 mag in the photographic band.

The star was estimated by one of us (SVA) on 241  plates taken from
JD\,2442812
to 8832 with the 40 cm astrograph in Crimea. Each plate was
estimated twice. The finding chart is
presented in Figure 1, and  magnitudes of the comparison stars
are given in Table~1.

Our data show that NSV\,10183 is a Cepheid variable with light elements:

\centerline{Max\ JD\ hel = 2444942.37 + 13.6299 $\times$ E.}
\hspace*{7.5cm}$\pm$.52\hspace*{7mm}$\pm$.0051
\vskip 3mm

The variability range is 12.4--13.2 pg. The study of the $O-C$ residuals
(Table 2 and Figure 2), obtained with our version of Hertzsprung's method
(Berdnikov, 1992),
clearly shows variations in the period. The final light curve (Figure 3)
was plotted taking into account seasonal shifts derived from the $O-C$
curve; thus it is corrected for period changes.

       As to classification of this variable, the distinct bump on the
ascending branch of the light curve  shows that it may be a classical Cepheid,
but, because of the rather flat curve in maxima, it 
may be a W Vir type star.
It is necessary to obtain a photoelectric light curve for certain classification.

\centerline{Table 1}
\begin{center}
\begin{tabular}{cc}
\hline
\\
$Comparison$ & $Mag$\\
$Star$ & $pg$\\
\hline
a&11.86\\
b&12.48\\
c&12.93\\
d&13.45\\
\hline
\\
\end{tabular}
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\centerline{\epsffile{4287-f1.ps}}
\centerline{Figure 1}

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\centerline{2}
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\epsfxsize=8cm
\centerline{\epsffile{4287-f2.ps}}
\centerline{Figure 2}
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\epsfysize=5cm
\epsfxsize=8cm
\centerline{\epsffile{4287-f3.ps}}
\centerline{Figure 3}
\vskip 2mm

\centerline{Table 2}
\vskip 1mm
\begin{tabular}{ccrrc}
\hline
Max JD hel & Error & E & O$-$C & Number\\
2400000+ & & & & of observations\\
\hline
\\
42925.44&  .05&    $-$148&    .31&    76\\
43306.95&  .08&    $-$120&    .18&    60\\
43907.10&  .08&     $-$76&    .61&    27\\
44057.37&  .12&     $-$65&    .96&    24\\
44791.27&  .15&     $-$11&  $-$1.17&    10\\
45430.64&  .12&      36&  $-$2.41&    13\\
46632.00&  .11&     124&   $-$.48&    15\\
46975.27&  .07&     149&   2.04&    16\\
\hline
\end{tabular}
\end{center}

\vskip 1mm
This work was partially supported by the Russian Foundation for Basic Research 
through grant No.\,95-02-05189 to one of us (SVA).
\vskip .5cm
\beginauthors
\authorsrightcol
S.V. ANTIPIN
L.N. BERDNIKOV
Sternberg Astronomical Institute
13, Universitetskij prosp.
Moscow 119899, Russia
\endauthors
\vskip -1cm
\references

Berdnikov, L.N., 1992, {\it Pisma v Astron. Zh.}, {\bf 18}, 519

Hoffmeister, C., 1966, {\it Astron. Nachr.}, {\bf 289}, 139

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