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\IBVShead{4942}{18 August 2000}

\IBVStitle{The false nova 1999 in the nearby galaxy IC 1613}

\IBVSauth{Fugazza, D.; Mantegazza, L.; Poretti, E.; Antonello, E.}

\IBVSinsto{Osservatorio Astronomico di Brera, Via E. Bianchi 46,
I-23807 Merate, Italy
\\ \indent e-mail: fugazza@merate.mi.astro.it}

\SIMBADobj{EQ J010448.9+020528.8}
\IBVSkey{novae, long period variables, nearby galaxies}
\IBVSabs{The so-called nova 1999 in IC 1613 is in fact a very red}
\IBVSabs{variable star with a period of 631d.}


\begintext

King et al.\ (1999) announced the discovery of a nova in the nearby
galaxy IC 1613 on the basis of unfiltered images taken on October 12
and 13, 1999. According to them the object had a brightness of about
18\fmm5 and the limiting magnitude of their frames was about 19.  The
analysis of their archival images showed that the object was present
since August 23 with about the same brightness, but it was invisible on
Aug.~18.

As we have been observing IC 1613 since 1995 to detect variable stars
(Antonello et al.\ 1999) and the so--called nova falls in our Field B
(Antonello et al.\ 2000), we had the opportunity to check that its
coordinates are coincident within the uncertainties with those of our
variable V2950B. According to our 57 measurements, taken between
October 1995 and October 1998 with the 0.9-m Dutch telescope at La
Silla Observatory, this is an object with an amplitude of variation in
unfiltered light of about 2\fmm5 in a period of about 645 days.  Our
exposures were of 30 min in duration and the limiting magnitude is about 24.
According to this period the epochs of the observations by King et
al.\ (1999) falls a few days before the maximum brightness of the
star.

We got other 6 images in unfiltered light with the 1.5-m telescope at
the Observatorio Astronomico Nacional of San Pedro Martir between
October 12 and 19, 1999, i.e.\ just by chance we observed at the same
dates of the detection of the presumed nova by King et al.\ (1999).
According to our data the star brightness did not change by more than
0\fmm1 with a mean value of 18\fmm52 in our unfiltered light photometric
system (see Antonello et al.\ 1999). The new data allowed us to improve
the period, obtaining 631 days.  Our measurements phased with this
period are shown in Fig.~1, where the 1999 data are plotted as crosses
and the best fitting sine wave is shown as a dashed line. The zero
phase corresponds to JD 2450795.50.

\begin{table}[b]
\caption{Filtered light measurements.}
\begin{center}
\begin{tabular}{lllll} \hline
JD     & $V$  & $V-R$ & $V-I$& $B-V$ \\ \hline
2445973.88 & 21.20 & 1.26 & 3.47 & 2.02 \\
2450305.90 & 20.16 & 0.95 & --- & ---  \\
2450725.80 & 22.52 & --- & 4.36 & ---  \\
\hline
\end{tabular}
\end{center}
\end{table}

\IBVSfig{8cm}{4942-f1.ps}{Unfiltered data phased with $P=631$~d;
the crosses correspond to the October 1999 observations. The dotted line is the
best fitting sine wave}

\IBVSfig{10cm}{4942-f2.ps}{Unfiltered image taken on October 17, 1996:
the star erroneously announced as a nova is a long period variable}

\vskip-22pt
We were able to find three measurements of this star in filtered light,
which are listed in Table~1.  The first one is by Freedman (1988), the
second one was obtained from our $V$ and $R$ images, and the third was
measured by us on the Cole et al.\ (1999) frames.  The star varies of
at least 2\fmm4 in $V$ light and its colour is very red, having $V-I$
of about 4.

Fig.~2 shows the image of V2950B in unfiltered light taken by us on October 
17, 1996, i.e.\ three years before the announcement of the detection as a nova.
At that time the star had a magnitude of 19.2.

\references

Antonello, E., Mantegazza, L., Fugazza, D., Bossi, M., Covino, S.,
1999, {\it A\&A}, {\bf 349}, 55

Antonello, E., Fugazza, D., Mantegazza, L., Bossi, M., Covino, S.,
2000, {\it A\&A}, in press

Cole, A.A., Tolstoy, E., Gallagher, J.S., 1999, {\it AJ}, {\bf 118}, 1657

Freedman, W.L., 1988, {\it AJ}, {\bf 96}, 1248

King, J.Y., Modjaz, M., Li, W.D., 1999, {\it IAU Circ.}, No.\ 7287

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