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\IBVShead{4447}{3 March 1997}

\title{Variable stars in the Globular Cluster NGC 4372}

\begintext

    The globular cluster NGC\,4372 ($C1223-724, l = 301\fdg0, 
b =-9\fdg 9$) has a low concentration (CC XII) and relatively 
low metallicity. Estimates of the latter range from $-$1.66 (Bica \& Pastoriza, 1983) to $-$2.16 (Frogel et al., 1983). The integral 
spectral class, F5 (Hesser \& Shawl, 1985), favours the former value. 
The cluster has an apparent radius $r = 9\farcm3$ 
(Kukarkin, 1974) and tidal radius $r = 31\farcm6$ (Webbink, 1985). 

   In the first two editions of Catalogue of Variable
Stars in Globular Clusters (Sawyer, 1939, 1955) with reference to
a communication from H. Shapley there are 3 unpublished and 11 suspected 
variables in the cluster. However no data are given for these stars.
In a search for variables (Fourcade et al., 1966) two (type unknown)
were discovered at a considerable distance from the cluster center ($r > 11\farcmm$).
A further search (Kaluzny \& Krzeminski, 1993) detected 19 short-period SX Phe type variables and close binaries.
In the present study the search for RR Lyr type variables was made in the area
$r < 4\farcm5$ using the same $V$ and $B$ observations (Brocato et al., 1996)
in four overlapping fields with 3-6 consecutive exposures and applying
the same method of search for variable stars as in our previous papers 
(Kadla et al., 1996a,b). 
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\begin{center}
Figure 1. The color -- magnitude diagram for the globular cluster NGC\,4372.
   The suspected RR Lyrae stars are denoted by $\circ$
\end{center}
\vfill \eject

\centerline{2}
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Figure 2. Chart of the western part of the cluster. Variable stars are denoted by $\bigcirc$
\end{center}

\vskip 5mm
\centerline{Table 1. Positions and photometric data for suspected variables stars}  
\begin{center}
\begin{tabular}{rrrrr}
\hline
 $N$ & $X$\ \ \ & $Y$\ \ \  & $V$ & B$-$V\\
     & (arcsec) & (arcsec) &  & \\
\hline\noalign{\smallskip}
  1 &  $-$76.06 &  33.38 &  16.13 & 0.66\\ 
  2 &  $-$20.97 & $-$46.72 &  15.77 & 0.62\\ 
  3 &   $-$7.17 & $-$98.01 &  15.87 & 0.59\\ 
  4 &   $-$6.15 & 268.59 &  15.69 & 0.63\\
\hline                                        
\end{tabular}
\end{center}

\vskip 3mm
A comparison  of  the CMDs for the four fields revealed that the absorption in 
the southern part of the investigated area is less than in the northern part,
E(B$-$V) = 0.1. The resulting CMD corrected for differential absorption is shown in Figure 1. Data for the four stars in the instability strip, which are
suspected RR Lyr variables, are given in Table 1. Their positions are 
determined using as a reference frame the coordinate system given in the
paper by Kaluzny \& Krzeminski (1993) and are shown in the finding chart (Figure 2).
$V$ and $B-V$ values for V4 are corrected for differential absorption.
The short duration of the observations, less than 35 min in each color for
each field, did not permit the confirmation of the variability of these stars.
\vfill \eject

\centerline{3}
\vskip 1mm

We are grateful to the Russian Foundation for Basic Research for financial
support.
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\beginauthors  
\authorsrightcol
A.N. GERASHCHENKO 
Z.I. KADLA 
Yu.N. MALAKHOVA
Central Astronomical Observatory of 
the Russian Academy of Sciences at 
Pulkovo, 196140 Saint--Petersburg, 
Russia
e-mail: mal@pulkovo.spb.su
\endauthors


\references

 Bica, C.L.D. \& Pastoriza, M.G., 1983, {\it ApSS}, {\bf 91}, 99

Brocato, E., Buonanno, R., Malakhova, Yu. \& Piersimoni, A.M.,
 1996, {\it A\&A}, {\bf 312}, 80

Fourcade, C.R., Laborde, J.R., \& Albarraem, J., 1966, Atlas 
 y Catalogo de estrellas variables en cumulos globulares al sur de 
 $29\degr$, Cordoba 

Frogel, J.A., Cohen, J.G. \& Persson, S.E., 1983, {\it ApJ}, {\bf 275}, 773

Hesser, J.E.\& Shawl, S.J., 1985, {\it PASP}, {\bf 97}, 465

Kadla, Z.I., Gerashchenko, A.N. \& Malakhova, Yu.N., 1996a, 
 {\it IBVS}, No.\,4413 

Kadla, Z.I., Gerashchenko, A.N. \& Malakhova, Yu.N., 1996b, 
 {\it IBVS}, No.\,4414 

Kaluzny, J., \& Krzeminski, W., 1993, {\it MNRAS}, {\bf 264}, 785

Kukarkin, B.V., 1974, The General Catalogue of Globular Clusters
 of our Galaxies. Publishing House Nauka, Moscow

Sawyer, H., 1939, {\it Publ. David Dunlap Obs.}, {\bf 1}, No.\,4, 127

Sawyer, H., 1955, {\it Publ. David Dunlap Obs.}, {\bf 2}, No.\,2, 35

Webbink, R.F., 1985, IAU Symposium No.\,113, 541,
    eds by J. Goodman \& P. Hut, Reidel, Dordrecht


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