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\IBVShead{4218}{14 July 1995}

\title{Rediscovery of a Dwarf Nova, V725 Aquilae}

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\begintext

V725 Aql is listed as a dwarf nova by Vogt and Bateson (1982),
who identified a blue star on the Palomar Observatory Sky Survey plate. 
However, Bruch (1983) pointed out the lack of ultraviolet excess
in this star.

During the course of our systematic survey of dwarf novae
at the Ouda Station, Kyoto University, we found a \lq\lq new''
bright object in the vicinity of the cataloged position of
V725 Aql on March 8, 1995, and have made photometric
observations of this object on 8 nights between March 8 and
March 20 and on May 6.

All of our observations at the Ouda Station were done using
CCD camera (Thomson, TH7882 CDA, 576 $\times$ 384 pixels with
23 $\mu$m square pixel size) attached to the Cassegrain focus
of 0.6-m reflector with Johnson V-band filter (Ohtani et al.
1992).  The integration time was between 90 and 120~s
depending on the brightness of the object. The mode of 
2~$\times$ 2 on-chip summation was employed.
We reduced the data with the personal-computer-based PSF
photometry package developed by one of the authors (T.K.).
This package automatically subtracts bias-frames,
applies flat fielding and enables us to estimate the differential
magnitudes.

The accurate position of this object calculated using our CCD
image is 19\fh 56\fmm 45\fss 03 +10\degr 49\farcmm
32\farcs 7 (J2000.0) ($\pm$ 0.5 arcsec) using seven
GSC stars.  This position significantly differs from that in
Vogt and Bateson (1982).  However, on close examination of the
discovery paper (Rohlfs 1949) and the original finding chart
(Hoffmeister 1957), although the chart was small in scale,
the object currently in outburst seems to be within the
error of these papers.  Figure 1 shows the chart based on
our CCD image.  At the corresponding position
in the CV chart by Downes \& Shara (1993), there is a very faint
star.


Figure 2 shows the results of the differential photometry from
March 8 to 20.  The V magnitude of the comparison star is 11.9
(GSC) and the position is 19\fh 56\fmm 50\fss 88
+10\degr 46\farcmm 12\farcs 1 (J2000.0). The
average magnitudes on March 8 and on May 6 correspond
to 13.6 and 17.3, respectively. 

Rohlfs (1949) found three outbursts separated by about 1300 days.
Fuhrmeister (1991) surveyed 250 Sonneberg plate and found 
two additional outbursts.  These data seem to suggest a low
outburst frequency of this object.  However, no information
on identification was given.  Hazen (1995) tells that she
has looked at 264 plates of the region in the Harvard College
Observatory plate archive and has found 4 additional historical
outbursts.  She also tells that the position is not consistent
with the chart of Vogt and Bateson (1982) but seems to be
consistent with the position mentioned above.

All the facts above give good observational evidence
that the object we observed is the  \lq\lq real'' V725 Aql,
only despite the range of variability (13.7--16.2) (Rohlfs 1949)
which seems to be in contradiction with the new finding.  The problem
of the lack of ultraviolet excess claimed by Bruch (1983) seems
to be solved now.
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\centerline{2}
\epsfysize=11cm
\centerline{\epsffile{4218-f1.ps}}
\centerline{Figure 1: Chart of V725 Aql based on a CCD image}
\epsfysize=11cm
\centerline{\epsffile{4218-f2.ps}}
\centerline{Figure 2: Outburst light curve on March 8 -- 20, 1995}
\vfill \eject

\centerline{3}
\epsfysize=10cm
\centerline{\epsffile{4218-f3.ps}}
\centerline{Figure 3: Short-term variation of V725 Aql}
\vskip 5mm

Figure 3 seems to show short-term variability during outburst.
However, due to the shortness ($\sim$1 hours) of the observational
time at the Ouda Station, we could not confirm any periodicity.
It is left unclear what subtype of dwarf novae
V725 Aql belongs to. However, a long outburst recurrence time,
a rather large outburst amplitude and a rapid decline rate
($\sim$0.8 mag day$^{-1}$) from outburst imply that V725 Aql
may be either an infrequently outbursting SS Cyg-type
star or an SU UMa-type star which is currently caught
during a superoutburst.  The determination of the orbital period
and the close monitoring for future outburst are highly
encouraged.


The authors are grateful to M. Iida for calculating the
position of V725 Aql.  We thank B. Skiff for helping us 
to get original information on discovery papers.  Thanks are
also due to A. Nakamura and K. Hirosawa
for checking against catalogued minor planets.
Part of this work was supported by a Research Fellowship
of the Japan Society for the Promotion 
of Science for Young Scientists (T.K.).

\vskip 1cm
\beginauthors
\authorsrightcol
Daisaku NOGAMI
Seiji MASUDA
Taichi KATO
Department of Astronomy,
Faculty of Science, Kyoto University
Sakyo-ku, Kyoto 606-01, Japan
e-mail address(D.N.): 
nogami@kusastro.kyoto-u.ac.jp                       %email
\endauthors
\vfill \eject

\centerline{4}
\vskip 2mm
\references

Bruch, H., 1983, {\it IBVS}, No.\,2287

Downes, R.A., Shara, M.M., 1993, {\it PASP}, {\bf 105}, 127

Fuhrmeister, T., 1991, {\it MVS}, {\bf 12}, 94

Hazen, M., 1995, {\it JAAVSO} in press

Hoffmeister, C., 1957, {\it MVS}, {\bf 1}, 245

Ohtani, H., Uesugi, A., Tomita, Y., Yoshida, M., Kosugi, G.,
     Noumaru, J., Araya, S., Ohta, K., 1992, {\it Memoirs of the
     Faculty of Science, Kyoto University,
     Series A of Physics, Astrophysics, Geophysics and Chemistry},
     {\bf 38}, 167

Rohlfs, E.,  1949, {\it Ver\"off. Sternwarte Sonneberg}, {\bf 1}, No.\,3

Vogt, N., Bateson, F.M., 1982, {\it A\&A Suppl.}, {\bf 48}, 383


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