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\IBVShead{5233}{31 January 2002}

\IBVStitle{Period and proper motion of 1RXS J232953.9+062814}

\IBVSauth{Kimeswenger, S.; Schmeja, S.; Kitzbichler, M. G.; Lechner, M. F. M.; M\"uhlbacher, M. S.;  M\"uhlbauer, A. D.}

\IBVSinsto{Institut f\"ur Astrophysik, Leopold-Franzens-Universit\"at 
Innsbruck, Technikerstr.\ 25, A-6020 Innsbruck, Austria\\
\indent e-mail: stefan.kimeswenger@uibk.ac.at}

\SIMBADobjAlias{1RXS J232953.9+062814}{[WXD99] J232954.38+062810.2}

\IBVSabs{We present accurate astrometry and absolute calibrated R CCD }
\IBVSabs{photometry at two epochs, one during the decline after the }
\IBVSabs{last outburst and one back to the quiescent value.}

\begintext

Early in November 2001 an outburst of this dwarf nova system was reported (Uemura et al.\ 2001).
These authors also report the detection of superhumps with a period of 0\fday046311(12) and estimate 
a proper motion of 0\farcs1/year. The latter is of special interest, as it gives a hint that this 
object might be one of the nearest symbiotic 
binary systems.
We have investigated the object to improve those values.
CCD photometry 
was obtained at the Innsbruck 60-cm RC telescope during two runs on November~15, 2001 and December~10, 2001 using a 
Johnson $R$ filter. Data reduction and source extraction were performed as described in Bacher et al.\ (2001). We obtained
differential photometry relative to the star USNO 0900-20419578. Weak cirrus clouds during the first run did not 
allow an absolute calibration at that time.
During the other run 12 exposures of the nearby standard star HD 220954 were taken.
They have an rms of 0\fmm024 (and thus 0\fmm017 for the zero point error).
Using this calibration we were able to calibrate the comparison star to 
13\fmm76$\pm$0\fmm03.  This is in good agreement with the photographic
red magnitude of 13\fmm6 given in USNO A2 and GSC2.
Stacks of all images of a night were used to check the comparison star for long term stability by means of weak stars in the field.
The photometry of 1RXS~J232953.9+062814 (means of a night) yields 

\medskip

\centerline{
\begin{tabular}{l l}
JD 2452229.301 (Nov.\ 15, 2001): & $m_{\rm R}$ = 15\fmm57$\pm$0\fmm04\\
JD 2452254.258 (Dec.\ 10, 2001): & $m_{\rm R}$ = 15\fmm80$\pm$0\fmm03\\
\end{tabular}
}

\medskip

\noindent Although the decline clearly indicates a remnant of the outburst activity during the 
first night, we were unable to find the superhumps of up to 0\fmm3 as reported during the earlier phase
(Uemura et al.\ 2001). A frequency analysis using the PDM method (Stellingwerf 1978) shows only a very low
 probability of a period at 0\fday046. A better solution is found with 
0\fday022584. Visual inspection (Figs.\ 1 and 2) shows indeed 
that the latter period is more likely. It is clearly visible during the second night too, when the object had 
already declined to quiescence. The amplitudes are comparable for both nights.

\newpage


\IBVSfig{5.5cm}{5233-f1.eps}{
The photometry derived during the two nights folded with the period of 
0\fday04631112 (Uemura et al.\ 2001) and the first of our observations as zero 
point. The squares indicate the observations of November,
the triangles those of December. No indications of this period are found.} 

\vspace{-3mm}

\IBVSfig{5.5cm}{5233-f2.eps}{
The same as above but folded with a period of 0\fday022584. There is a clear 
sign of periodicity.
As the two observations are 110 periods apart, the quality of the period is very good.} 

\relax

Accurate astrometry based on 18 stars with $R < 18\fmm5$ surrounding the target
within 12 arcminutes was derived on 7 digitized survey plates. The epochs of the plates are given in Table 1.
The stars include the astrometric calibration stars AC2000 2052132 (= TYCHO-2 125895) and AC2000 2052114.

\vskip 2mm

\centerline{Table 1. The epochs of the plates used for the astrometry.}
\vskip 3mm
\begin{center}
\begin{tabular}{c l c c}
\hline
Type   &  Description  &  Plate Number & Epoch \\
\hline
DSS-1 & POSS-E Red Plate & XE582 & 1951.607 \\
DSS-1 & Quick-V Northern & N582 & 1983.612 \\
DSS-1 & Quick-V Northern & N612 & 1983.683 \\
DSS-2 & POSS-II Red & XP822 & 1986.77 \\
DSS-2 & POSS-II Blue & XJ821 & 1992.572 \\
DSS-2 & POSS-II Blue &  XJ822 & 1992.747 \\
DSS-2 & POSS-II Red & XP821 &  1993.639 \\
\end{tabular}
\end{center}

\noindent The rms of the reference frame stars is 0\farcs15 for the DSS-1 plate
 and less than  0\farcs09
for the other plates. This allows us to derive the position from the 
combination of the 7 plates to an accuracy of  0\farcs04
and of the proper motion to an accuracy of  0\farcs005/year (alpha)
 and   0\farcs003/year (delta).
The total proper motion is 0\farcs056$\pm$0\farcs005/year and thus about a 
factor  of two below that estimated by Uemura et al.\ (2001).

\IBVSfig{7.7cm}{5233-f3.eps}{
The positions of 1RXS J232953.9+062814 relative to the mean position on all 7 
frames; left: declination; right: right ascension.} 

The coordinates below are calculated for epoch and equinox J2000.0, using the mean position using
all plates (epoch 1981.859) and the obtained proper motion.

\medskip
\centerline{
\begin{tabular}{rcl lcl}
$\alpha_{\rm \tt J2000.0}$& = &$23\hr29\mm54\fsec402\, \pm 0\fsec04$ & $\qquad$PM$_{\alpha}$&=&$-0\farcs039\pm0\farcs005$/year\\
$\delta_{\rm \tt J2000.0}$& = &$06\deg28\arcm07\farcs89\, \,\ \pm 0\farcs04$ & $\qquad$PM$_{\delta}$&=&$+0\farcs040\pm0\farcs003$/year\\
\end{tabular}
}

\references

Bacher, A., Lederle, C., Gr\"omer, G.E., Kapferer, W., Kausch, W., Kimeswenger, S., 2001, {\it IBVS}, {\bf 5182}.
% \BIBCODE{2001IBVS.5182....1B}

Stellingwerf, R.F., 1978, {\it ApJ}, {\bf 224}, 953.
% \BIBCODE{2001ApJ...224..953S}

Uemura, M., Ishioka, R., Kato, T., Schmeer, P., Yamaoka, H., Starkey, D., Vanmunster, T., Pietz, J., 2001, {\it IAUC}, {\bf 7747}, 2.
%\BIBCODE{2001IAUC.7747....2U}

\endreferences

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