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\IBVShead{4871}{3 April 2000}

\IBVStitle{Revised Elements and CCD Light Curve for AQ Bootis}

\IBVSauth{Bl\"attler, E.}

\IBVSinsto{BBSAG, Schl\"usselacher 1, CH-8636 Wald, Switzerland; e-mail: blaettler-wald@bluewin.ch}

\SIMBADobjAlias{AQ Boo}{GSC 01460-00578}

\begintext

\IBVSTnam{AQ Boo = S\,8091 = GSC\,01460.578}

\IBVSTcoo{13\hr 47\mm 26.9\sec}{+17\deg 18\arcm 24\arcs}{2000.0}

\IBVSTobs{Private observatory, Schl\"usselacher, Wald, 0.15-m refractor}

\IBVSTdet{SBIG ST-7 CCD camera}

\IBVSTfil{None}

\IBVSfig{8.2cm}{4871-f1.eps}{CCD light curve (without filter) of AQ Boo folded with the elements (2)}

\IBVSTcomp{GSC\,01460.003}

\IBVSTchk{GSC\,01460.206}

\IBVSTsysn

\IBVSTdata{Upon request from blaettler-wald@bluewin.ch} %email


\IBVSTtyp{ EW }

\IBVSTrem{
\abovedisplayskip3pt
\belowdisplayskip3pt
AQ Bootis is one of the many variable stars detected at Sonneberg
Observatory by Hoffmeister (1964). In later articles, the
star was investigated by Meinunger \& Wenzel (1968) as well as by
Schmidt (1996), who assigned AQ Bootis to the EW class of
the eclipsing binaries and gave the approximate elements of variation
\begin{equation}
{\rm JD(min,hel)} = 2448716.724 + 0\fday333412 \times E.
\end{equation}
Due to a typographical error in the text, some degree of ambiguity as
to the correct value of the period remains, either 0\fday333412 or
0\fday33412. Our observational setup
yields photometry at the 0\fmm03 level. A total of 189 CCD
measurements during 6 nights from JD\,2451377 to
JD\,2451602 have been obtained. Due to the proximity of the comparison
star to AQ Boo, no correction for differential extinction was applied
to the data. From a long observing run covering 5.5 hours (JD\,2451602)
comprising both a primary as well as a secondary minimum it was
evident, that the true value of the period is close to 0\fday33314.
All our CCD observations are best represented by the new elements
\begin{equation}
{\rm JD(min,hel)} = 2451602.3922(6) + 0\fday33314114(8) \times E. 
\end{equation}
As can be seen in the following table, these elements of variation also
fit the initial minimum of the elements (1) to a satisfying degree.
\begin{center}
\normalsize
\begin{tabular}{llrll}
\hline
JD(hel) & Est.~err. & \multicolumn1c{$E$} & \multicolumn1c{$O-C$} & Reference \\
\hline
2448716.724 & & $-$8662.0 & +0.003 & Schmidt (1996)\\
2450518.517 & 0.003 & $-$3253.5 & $-$0.001 & Diethelm (1997)\\
2450941.4413 & 0.0013 & $-$1984.0 & +0.0011 & Diethelm (1998)\\
2451334.5469 & 0.0011 & $-$804.0 & +0.0001 & Bl\"attler (1999)\\
2451358.365 & 0.002 & $-$732.5 & $-$0.001 & Bl\"attler (1999)\\
2451602.3928 & 0.0009 & 0.0 & +0.0006 & Bl\"attler (2000)\\
2451602.5585 & 0.0003 & 0.5 & $-$0.0003 & Bl\"attler (2000)\\
\hline
\end{tabular}
\end{center}
AQ Bootis is a W UMa type eclipsing binary, whose primary minimum is a
transit, while the secondary is an occultation. Some of the scatter in
Figure~1 indicates, that its light curve is not absolutely stable.
}

\references

Bl\"attler, E., 1999, {\it BBSAG Bulletin}, {\bf 120}

Bl\"attler, E., 2000, {\it BBSAG Bulletin}, {\bf 122}

Diethelm, R., 1997, {\it BBSAG Bulletin}, {\bf 114}

Diethelm, R., 1998, {\it BBSAG Bulletin}, {\bf 118}

Hoffmeister, C., 1964, {\it Astron.\ Nachrichten}, {\bf 288}, 49

Meinunger, L., Wenzel, W., 1968, {\it Ver\"off.\ Sternw.\ Sonneberg}, {\bf
7}, 389

Schmidt, E. G., 1996, {\it Publ.\ Astr.\ Soc.\ Pacific}, {\bf 108}, 1105

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