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\IBVShead{4530}{31 October 1997}

\IBVStitletl{V829 AQUILAE IS A PULSATING STAR}{ WITH A VARIABLE LIGHT CURVE}

\IBVSauth{R. DIETHELM}
\IBVSinsto{BBSAG, Rennweg 1, CH-4118 Rodersdorf, Switzerland, e-mail: diethelm@astro.unibas.ch}

\SIMBADobj{V829 Aql}
\IBVStyp{ DSCT, RR }
\IBVSkey{CCD-photometry}

\begintext

The star V829\,Aquilae = BD\,+03\deg4145 = AN\,122.1935 =
GSC\,484.00065 ($\alpha_{J2000}: 19\hr 46\mm 57\sec; \delta_{J2000}:
+03\deg 30\arcm 28\arcs$; spectral type: F5) was found to be variable
by Hoffmeister (1935) from photographic photometry at Sonneberg
Observatory, Germany. He remarked that the star was ``difficult'' and
``possibly an eclipsing binary''. Based on this scant information, the
author started a visual survey (Diethelm, 1977) that led to the
determination of provisional elements. These elements were adopted in
the GCVS (Khopolov et al., 1985).

\bigskip

\IBVSfig{8.5cm}{4530-f1.eps}{Unfiltered CCD light curve of
V829 Aquilae during six nights in 1997}

\vfil\eject

In order to investigate the validity of the preliminary elements, we
reobserved V829 Aquilae with the 35cm SC-reflector of R. Szafraniec
Observatory, Metzerlen, Switzerland, equipped with an SBIG ST-6 CCD
camera at its prime focus. The unfiltered CCD photometry is accurate
at the 0.1 magnitude level for objects as bright as V829 Aquilae
(11th magnitude). Since both the comparison star (GSC\,484.00267) as
well as the check star (GSC\,484.00227) lie within a few arcminutes of the variable, no extinction correction was necessary. A total of 61
observations in 1995 and 88 observations in 1997 were secured.  In
Figure 1, we present the data from six nights in 1997 (JD\,2450645,
2450650, 2450651, 2450656, 2450658 and 2450669) as an example for the
photometric behaviour of V829 Aquilae. The comparison star proved to
be constant during all the 25 nights when observations were gathered.

From these examples it is apparent, that the variation of V829
Aquilae shows a complex nature of a pulsating type. While in some
nights, we observe a well established asymmetric pulsation light curve
with a period of close to 0.3 days and an amplitude of about 0.4
magnitudes, in other nights the star shows little variation at an
intermediate brightness level, which is reminiscent of the behaviour
of VZ Cancri (Arellano Ferro et al., 1994; Cox et al., 1984) or AC
Andromedae (Fitch and Szeidl, 1976).

Based on this comparison we conclude that V829 Aquilae is probably
a multimode radial pulsator very much deserving further attention.  We
have tried to find the primary period of pulsation from our data. The
1997 observations can be fitted reasonably well with a principal
period of 0\fday292, but the data from 1995 cannot be presented
with this period value. Our data are not numerous enough to establish
the period values with any certainty. Any researcher wishing to use
our data for a comprehensive period study is kindly invited to contact
the author at the e-mail address given above.

This research made use of the SIMBAD database operated by the CDS,
Strasbourg, France. The author wishes to thank the ``Emilia
Guggenheim-Schnurr Foundation'' for financial support.

\references
Arellano Ferro, A., Nu\~nez, N. S., Avila, J. J., 1994, {\it PASP}, {\bf 106}, 696

Cox, A. N., McNamara, B. J., Ryan, W., 1984, {\it ApJ}, {\bf 284}, 250

Diethelm, R., 1977, {\it BBSAG Bulletin}, {\bf 34}, 5

Fitch, W. S., Szeidl, B., 1976, {\it ApJ}, {\bf 203}, 616

Hoffmeister, C., 1935, {\it Astron.\ Nachr.}, {\bf 255}, 401

Kholopov, P. N. et al., 1985, {\it General Catalogue of Variable Stars}, Moscow

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