\documentclass[twoside]{article}
\usepackage{ibvs2}
\usepackage{epsf}

\begin{document}

\IBVShead{5481}{25 November 2003}

\IBVStitle{Four RR Lyrae Stars with Variable Periods in Ophiuchus}

\IBVSauth{H\"{a}ussler, K.$^1$; Berthold, T.$^1$$^,$$^2$; Kroll, P.$^2$}

\IBVSinst{Bruno-H.-B\"{u}rgel-Sternwarte, T\"{o}pelstr. 46, D-04746 Hartha, Germany}

\IBVSinst{Sternwarte Sonneberg, Sternwartestr. 32, D-96515 Sonneberg, Germany}

\indent {
\small{email: sternwartehartha@lycos.de, tb@stw.tu-ilmenau.de, pk@stw.tu-ilmenau.de}}

\SIMBADobj{V823 Oph}
\SIMBADobj{V825 Oph}
\SIMBADobj{NSV 9820}
\SIMBADobj{NSV 10115}

\begintext


The discovery of the variability of these stars has been reported by 
Hughes-Boyce and Huruhata (1942) and Hoffmeister (1966, 1967); 
but there were no ephemeris published until today.
Photographic plates of a field centered around 67 Oph, 
taken with the Sonneberg Observatory 40cm Astrograph during three intervals spread 
over the years from 1938-1994,
were used to check the behaviour of these objects (see \mbox{Table 1}).
To avoid effects of cycle count ambiguities due to the somewhat inauspiciously 
distributed plates with large gaps in time, importance has been attached to
get well-fitted composite light curves representing all available observations. Therefore 
the reported period changes represent the smallest value of period alteration
suitable to achieve this aim. The elements listed below were obtained by means of 
least-squares solutions.

Photographic amplitudes were derived with respect to magnitudes of the 
comparison stars given in Table 2. Individual data are available upon request.

\vskip 3mm
\parindent0mm
{\em Remarks:}
\vskip 3mm
{\em V823 Oph}

Elements valid for J.D. 2429100-2441200 and J.D. 2444000-2449500 resp.

\vskip 3mm
{\em V825 Oph}

Elements valid for J.D. 2429700-2441200 and J.D. 2443300-2449500 resp.
\vskip 3mm
{\em NSV 9820}

Elements given below are at least valid for an interval of JD 2438200-2449500.
Unfortunately there were not enough older plates available 
to determine the date of the period change as well as the value of the period acting in the time
before the interval mentioned above. The star was announced by Hoffmeister to be an eclipsing binary of EB type.

\vskip 3mm
{\em NSV 10115}

Elements valid for J.D. 2429100-2440500 and J.D. 2443300-2449500 resp.

\vskip 3mm

This research made use of the SIMBAD data base, operated by the CDS
at Strasbourg, France.




%\pagebreak
%\clearpage
%\large
%\begin{samepage}
\IBVS2fig{7cm}{5481-f1.eps}{Composite light curve of V823 Oph}{5481-f2.eps}{(O$-$C) diagram for V823 Oph}
\IBVS2fig{7cm}{5481-f3.eps}{Composite light curve of V825 Oph}{5481-f4.eps}{(O$-$C) diagram for V825 Oph}
\IBVS2fig{7cm}{5481-f5.eps}{Light curve of NSV 9820 (J.D. 2438258 $-$ 2449475)}{5481-f6.eps}{(O$-$C) diagram for NSV 9820}
\IBVS2fig{7cm}{5481-f7.eps}{Composite light curve of NSV 10115}{5481-f8.eps}{(O$-$C) diagram for NSV 10115}

%%\IBVSfigKey{5481-f1.eps}{V823 Oph}{light curve}
%%\IBVSfigKey{5481-f2.eps}{V823 Oph}{O-C diagram}
%%\IBVSfigKey{5481-f3.eps}{V825 Oph}{light curve}
%%\IBVSfigKey{5481-f4.eps}{V825 Oph}{O-C diagram}
%%\IBVSfigKey{5481-f5.eps}{NSV 9820}{light curve}
%%\IBVSfigKey{5481-f6.eps}{NSV 9820}{O-C diagram}
%%\IBVSfigKey{5481-f7.eps}{NSV 10115}{light curve}
%%\IBVSfigKey{5481-f8.eps}{NSV 10115}{O-C diagram}

%\end{samepage}


\begin{table}[!ht]
\centerline{Table 1. Summary of this paper}
\vskip 3mm
\begin{center}
\begin{tabular}{lcrrrrcc}
\hline
Star   & Type &  Epoch    &Period &Max. & Min. & M$-$m & No. of \\
       &      & 2400000+ & (day)  &     &      &     & Plates   \\
\hline
V823 Oph (1) & RRab  &29785.481     & 0.5176480      & 14\fmm7 & 15\fmm5  & 0\fper15 &103 \\
             &       &  $\pm$13     &    $\pm$8      &         &          &          &\\
V823 Oph (2) &       &49154.516     & 0.5176251      &         &          &          &93 \\
          &          &  $\pm$18     &   $\pm$31      &         &          &          &\\
V825 Oph (1) & RRc   &29816.434     & 0.2940934      & 13\fmm7 & 14\fmm2  &          &114 \\
             &       &   $\pm$6     &    $\pm$3      &         &          &          &\\
V825 Oph (2) &       &48802.505     & 0.2941175      &         &          &          &133 \\
             &       &  $\pm$16     &   $\pm$24      &         &          &          &\\
NSV 9820     & RRab  &48801.529     & 0.5326038      & 14\fmm6 & 15\fmm5  & 0\fper12 &217 \\
             &       &  $\pm$11     &   $\pm$10      &         &          &          &\\
NSV 10115 (1)& RRab  &29786.519     & 0.5440501      & 15\fmm0 & 16\fmm1  & 0\fper13 &88 \\
             &       &  $\pm$14     &   $\pm$10      &         &          &          &\\
NSV 10115 (2)&       &49124.475     & 0.5440106      &         &          &          &56 \\
             &       &  $\pm$15     &   $\pm$41      &         &          &          &\\

\hline

\end{tabular}
\end{center}
\end{table}


\begin{table}[!hb]
\centerline{Table 2. Comparison stars and cross references}
\vskip 3mm
\begin{center}
\begin{tabular}{ccrcr}
\hline
    &  V823 Oph           &     &  V825 Oph          &\\
    &  HV 11044           &     &  HV 11047          & \\
    &  USNO 0900-10538562 &     &  USNO 0900-10598218& \\
\hline
Comp. No.  &  USNO      & m$^*$     & USNO      & m$^*$\\
\hline
1   &  0900-10551987 &  14\fmm3  & 0900-10595254 & 13\fmm5\\
2   &  0900-10540298 &  15\fmm0  & 0900-10608192 & 14\fmm0\\
3   &  0900-10538956 &  15\fmm3  &         & \\
4   &  0900-10541236 &  15\fmm7  &         & \\
\hline
&&&&\\
&&&&\\
\hline
    & NSV 9820           & & NSV 10115 &\\
    & S 9844             & & S 9287    &\\
    & USNO 0900-10833595 & & USNO 0900-11413039 & \\
\hline
Comp. No.  &  USNO     & m$^*$     & USNO     & m$^*$\\   
\hline
1   & 0900-10828563 & 14\fmm4&  0900-11409203 &  15\fmm4\\
2   & 0900-10834041 & 14\fmm9&  0900-11412225 &  16\fmm1\\
3   & 0900-10826923 & 15\fmm1&          &   \\
4   & 0900-10831651 & 15\fmm3&           &  \\
\hline

\end{tabular}
\end{center}
\centerline{\normalsize $^*$ Magnitudes refer to the B values of the USNO$-$A2.0 catalogue}
\end{table}


\clearpage

\begin{table}[!ht]
\centerline{\normalsize Table 3. Heliocentric times of maxima and $O-C$ values according to the elements derived in this paper;}
\centerline{\normalsize the more recent second set of elements was used in the cases with two given sets.}
\vskip 3mm
\begin{center}
\begin{tabular}{lcrrlcrr}
\hline
Star   &  JD (max.$^*$) &Epoch &$O-C$  &  Star   &  JD (max.$^*$) &Epoch &$O-C$  \\
\hline
V823 Oph&29785.481&$-$37418&$-$0.539&V825 Oph&47388.390&$-$4808&0.002\\
&29786.522&$-$37416&$-$0.533&&47390.470&$-$4801&0.023\\
&29843.446&$-$37306&$-$0.548&&47391.347&$-$4798&0.018\\
&38528.528&$-$20528&$-$0.180&&47395.434&$-$4784&$-$0.013\\
&39682.428&$-$18299&$-$0.066&&47418.349&$-$4706&$-$0.039\\
&39683.420&$-$18297&$-$0.109&&48802.482&0&$-$0.023\\
&39684.461&$-$18295&$-$0.104&NSV 9820&29808.450&$-$35660&$-$0.430\\
&39712.391&$-$18241&$-$0.125&&29816.447&$-$35645&$-$0.422\\
&41150.468&$-$15463&$-$0.011&&39685.503&$-$17116&0.019\\
&45087.521&$-$7857&$-$0.014&&39708.397&$-$17073&0.011\\
&45115.486&$-$7803&$-$0.001&&40444.438&$-$15691&$-$0.006\\
&47387.377&$-$3414&0.033&&40803.395&$-$15017&$-$0.024\\
&48362.554&$-$1530&0.005&&41179.418&$-$14311&$-$0.019\\
&49154.493&0&$-$0.023&&45492.490&$-$6213&0.028\\
V825 Oph&29786.438&$-$64659&1.278&&45916.405&$-$5417&$-$0.010\\
&29788.495&$-$64652&1.276&&46507.630&$-$4307&0.025\\
&29816.433&$-$64557&1.273&&47386.398&$-$2657&$-$0.003\\
&29843.474&$-$64465&1.255&&48801.513&0&$-$0.016\\
&29844.389&$-$64462&1.288&NSV 10115&29785.438&$-$35547&$-$1.091\\
&39651.484&$-$31115&0.446&&29786.522&$-$35545&$-$1.095\\
&39684.461&$-$31003&0.481&&29816.433&$-$35490&$-$1.105\\
&39686.492&$-$30996&0.454&&38901.500&$-$18791&$-$0.471\\
&39702.398&$-$30942&0.477&&39611.517&$-$17486&$-$0.388\\
&39712.391&$-$30908&0.470&&39648.507&$-$17418&$-$0.391\\
&45492.490&$-$11254&$-$0.017&&39684.461&$-$17352&$-$0.342\\
&45822.489&$-$10132&$-$0.017&&46298.342&$-$5195&0.002\\
&46272.507&$-$8602&0.001&&46554.584&$-$4724&0.015\\
&46288.406&$-$8548&0.017&&47387.432&$-$3193&$-$0.017\\
&46506.628&$-$7806&0.004&&48067.449&$-$1943&$-$0.014\\
&47368.432&$-$4876&0.044&&49124.489&0&0.014\\
\hline

\end{tabular}
\end{center}
\centerline{\normalsize $^*$ Mid-exposure times of plates with brightest observations}
\end{table}

\references

Hoffmeister, C., 1966, {\it Astron. Nachr.}, {\bf 289}, 139

Hoffmeister, C., 1967, {\it Astron. Nachr.}, {\bf 290}, 43

Hughes-Boyce, E., Huruhata, M., 1942, {\it Harvard Annals}, {\bf 109}, 4

\endreferences


\IBVSedata{5481-t4.txt}
%\IBVSdataKey{5481-t4.txt}{NSV 10115}{photometry}
\IBVSedata{5481-t5.txt}
%\IBVSdataKey{5481-t5.txt}{NSV 9820}{photometry}
\IBVSedata{5481-t6.txt}
%\IBVSdataKey{5481-t6.txt}{V823 Oph}{photometry}
\IBVSedata{5481-t7.txt}
%\IBVSdataKey{5481-t7.txt}{V825 Oph}{photometry}

\end{document}

