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\IBVShead{4440}{19 February 1997}
 
\title{A SUSPECTED RED VARIABLE IN THE ERROR BOX OF GRB\,970111}
\begintext
 
GRB 970111 is a gamma--ray burst detected by the satellite BeppoSAX on
January 11, 1997 (Costa et al. 1997). Soon after the event, we observed the
field of GRB 970111 (Guarnieri et al. 1997) with the 1.5-meter telescope 
(+BFOSC) of the Bologna University and compared it to the Digitized Sky Survey 
(DSS). We noticed on the $R$ frames the clear presence of a star (Figure 1) which
was barely visible on the DSS (whose limiting magnitude is $R\sim20.5$). 
The star is also practically invisible on the Palomar Sky Survey
red plates and absent on the blue ones (limiting magnitude $\sim21$ 
for both). From the DSS we deduced the coordinates of this object:

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\centerline{
$\alpha$=15\fh 28\fmm 45\fs; $\delta$=+19\degr 47'15''
(equinox 2000.0),}

\vskip 1mm\noindent
with a conservative error of $\pm$5'' for both values. The star is inside the
GRB 970111 error box communicated by Hurley et al. (1997; see also Figure 1).
No variable object within a circle of radius 10' and centered on these 
coordinates is mentioned in the SIMBAD database.

From 5 frames (3 in $R$ band, 1 in $B$ and 1 in $V$, respectively) collected 
between Jan. 15 and Jan. 31 1997, we determined the magnitudes of the star by 
means of the DAOPHOT II package (Stetson 1987) and the {\sl ALLSTAR} procedure 
implemented in MIDAS. The entire log of observations, together with the Palomar data, is reported in Table 1.
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\centerline{Table 1. Available magnitudes and color indices for the variable}
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\begin{tabular}{ccccccc}
\hline
JD & $B$ & $V$ & $R$ & $B-V$ & $V-R$ & Source \\
\hline
\\
 2433391.90 & $>$21 & --- & $\sim$21 & --- & --- & Palomar plates \\
 2450463.68 & --- & --- & 19.90 & --- & --- & 1.5m+BFOSC \\
 2450465.71 & --- & --- & 19.93 & --- & --- & 1.5m+BFOSC \\
 2450479.65 & $>$21 & 20.34 & 19.80 & $\sim$1.2 & 0.54 & 1.5m+BFOSC \\
\hline
\end{tabular}
\end{center}
\vskip 1mm

The calibration has then been performed with the use of the photometric 
standards in the field of PG 1047+003 (Landolt 1992).
The star, on January 15 1997, was at $R=19.90\pm0.05$, thus showing a 
variation of more than a magnitude with respect to the Palomar red plates
(April 1950), while on January 17 the $R$ magnitude was $19.93\pm0.05$.
On January 31 its magnitude in the $R$ band was found to be $19.80\pm0.05$.
During the same night, its $V-R$ color index was 0.54. Unfortunately, the 
object was too faint to be visible in the $B$ band, even with an exposure time 
of 50 minutes; we can however give an indicative $B-V$ color index of 
$\sim$1.2 by comparing the $V-R$ of the star with those of field stars with 
known $B-V$ color indices. These colors suggest that this object is a 
mid--late K spectral 
type star, depending on the luminosity class (Lang 1992).
All this seems to indicate that this suspected variable might be a long period
red star.
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Figure 1.
The field (9'$\times$9') of the suspected variable in the Johnson $R$ 
band (exposure time: 20 minutes), observed on January 15, 1997. The star is 
indicated by the ticks. North is at top, east is to the left. The northern
part of GRB 970111 error box by Hurley et al. (1997) is also reported
\end{center}
\large
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\beginauthors
NICOLA MASETTI
Dipartimento di Astronomia
Universit\`a di Padova
vicolo dell'Osservatorio, 5
I-35122 Padua, Italy 
\vskip .8cm
\authorsrightcol
CORRADO BARTOLINI
ADRIANO GUARNIERI 
ADALBERTO PICCIONI
Dipartimento di Astronomia
Universit\`a di Bologna
via Zamboni, 33
I-40126 Bologna, Italy
\endauthors

\references

 Costa E., Feroci M., Piro L. et al., 1997, {\it IAU Circ.}, No.\,6533

 Guarnieri A., Bartolini C., Piccioni A. et al., 1997, {\it IAU Circ.}, No.\,6544

 Hurley K., Kouvelioutou C,  Fishman G., Meegan C., 1997, {\it IAU Circ.}, No.\,6545

 Landolt A.U., 1992, {\it AJ}, {\bf 104}, 340

 Lang K.R., 1992, {\it Astrophysical Data: Planets and Stars}. 
 Springer--Verlag, New York

 Stetson P.B., 1987, {\it PASP}, {\bf 99}, 191
 
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