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\input ibvs2.sty
\input ibvst.sty

\begin{document}

\IBVShead{5219}{9 January 2002}

\IBVStitle{GSC 628\_290: a new EW/KW variable}

\IBVSauth{Behrend, R.$^1$; Buil, Ch.$^2$; Antonini, P.$^3$; Demeautis, Ch.$^4$}

\IBVSinst{Geneva Observatory, CH-1290 Sauverny, Switzerland,
email: raoul.behrend@obs.unige.ch}

\IBVSinst{Ramonville Saint Agne Observatory, 10 Domaine de la Ch\^eneraie,
F-31520 Ramonville Saint Agne, France, email: christian.buil@wanadoo.fr}

\IBVSinst{Bedoin Observatory, 47 rue Guillaume Puy, F-84000 Avignon, France,
email: pierre.antonini@wanadoo.fr}

\IBVSinst{Village-Neuf Observatory, 9 rue de Huningue, F-68300 Saint-Louis, France,
email: sky.walker@wanadoo.fr}

\SIMBADobj{GSC 628-290}

\begintext

\IBVSTnam{GSC 628\_290}

\IBVSTcoo{01\hr48\mm43\sec64}{$+13$\deg04\arcm11\farcs6}{J2000}

\IBVSfig{9cm}{5219-f1.eps}{Unfiltered light curve of GSC 628\_290}

\IBVSTobs{
Ramonville Saint Agne Observatory (IAU astrometric code 959), 0.19m f/d=4
reflector \\
Bedoin Observatory (code 132), 0.16m f/d=3.5 reflector \\
Village-Neuf Observatory (code 138), 0.20m f/d=6.3 Schmidt--Cassegrain
telescope
}

\IBVSTdet{KAF 400 CCD at 959 and 132, KAF 401e CCD at 138}

\IBVSTfil{None, roughly $R$}

% \IBVSTcomp{****}

\IBVSTsysn

\IBVSTdata{Upon request}

\IBVSTrem{
The variability of GSC~628\_290 was found by Buil on CCD frames taken around 1998-08-29
(circles in Figure~1), during a test of implementation in his {\tt Iris} software
of an optimal image subtraction algorithm for supernovae photometry.
Antonini made several series of observations (1998-11-06, squares; 1998-11-07,
diamonds; 1998-11-20, 4-branches stars; 1998-11-24, triangles;
1998-12-07, 5-branches stars)
to establish the light curve and a preliminary period.
Demeautis observed GSC~628\_290 on 2001-10-12 (pentagons) to confirm the light curve and to better determine the period.
The eighth order Fourier sum that was adjusted on the observations includes two additional constants to account at the first level of approximation for the different (unfiltered) photometric
systems of each observer. The mean magnitude, the sixteen parameters of the periodic terms, the two constants, and the period are solved by
least square technics using all the observations and their uncertainties.
The time of a minimum is computed by a cut in the adjusted Fourier series near the principle minimum. The resulting light curve is shown in Figure~1.
The numerical values obtained with the {\tt CourbRot} software (Behrend, 2001)
are as follows:
\begin{eqnarray*}
    \textrm{HJD of a principal minimum} &=& 2452194.8429 \pm 0.0006 \\
    \textrm{Period} &=& 0\fday38176699 \pm 0\fday00000025 \\
    \textrm{Total variation} &=& 0.63 \pm 0.01 \,\textrm{mag}
\end{eqnarray*}
The shape of the light curve indicates that the variability type
of GSC~628\_290 is probably EW/KW.}

\reference

   Behrend, R., 2001, {\it Orion}, {\bf 304}, 12

\end{document}
