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\usepackage{ibvs2}
\usepackage{epsf}

\begin{document}

\IBVShead{5523}{16 April 2004}

\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{V1083 Oph}
\SIMBADobj{V1089 Oph}
\SIMBADobj{V1093 Oph}
\SIMBADobj{V1095 Oph}

\begintext

\vspace*{-0.7cm}

\noindent{
The discovery of the variability of these stars has been reported by 
Hoffmeister (1966, 1967). 
No ephemeris is known for V1089 Oph until today and, in the other cases, the published
elements were outdated because of strong period variations.
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}).
The elements listed below were obtained by means of least-squares solutions. 
Published times of maximum for V1083 Oph, V1093 Oph and V1095 Oph (Savin 1988a,b and Surikov 1982)
were included in this analysis. 

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

\vskip 2mm
\parindent0mm
{\em Remarks:}
\vskip 1mm
{\em V1083 Oph}

The ephemeris published by Savin (1988a) has been found in need of improvement.
Now, the elements listed in Table 1 are valid for J.D. 2429100-2441200 and J.D. 2444000-2449500 resp.
A supplementary quadratic solution is given because this represents the given minima 
timings in a comparable way like the linear ones. This set of elements is valid over
the whole interval.

\vskip 1mm
{\em V1089 Oph}

Elements valid (1982) for J.D. 2429700-2449500.
Due to a apparent companion the minimal magnitudes are somewhat uncertain.
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.
 
\vskip 1mm
{\em V1093 Oph}

First elements were derived by Savin (1988b); the GCVS lists an E0 according to Hoffmeister(1966)
and an erroneous period of 4.03 days.
Our elements given below are at least valid for an interval of JD 2438200-2449500.
The same problem as described in the case of V1089 Oph appeared for the period change.
Only the observations from J.D. 2438258-2449488 were displayed in the light curve (Fig. 5) because of
the uncertainties concerning the set of elements valid prior to this date.

\vskip 1mm
%\newpage
{\em V1095 Oph}

First elements were derived by Surikov. According to our observations the period turned out to be variable.
Elements are valid for J.D. 2425400-2430000 and J.D. 2439000-2449500 resp.
A quadratic fit was applied for the same reasons like in V1083 Oph.


\newpage


\begin{table}[!ht]
\normalsize 
\centerline{Table 1. Summary of this paper}
\vskip 3mm
\begin{center}
\begin{tabular}{lcrrcrrcc}
\hline
Star          & Type  &   Epoch      &Period         &Quad. Term   &  Max.   & Min.     & M$-$m    & No. of \\
              &       &  2400000+    & (day)         &  $*10^{-10}$&         &          &          & Plates   \\
\hline
V1083 Oph (1) & RRab  &38258.418     & 0.5522898     &             & 15\fmm3 & 16\fmm7  & 0\fper20 &88 \\
              &       &  $\pm$15     &    $\pm$7     &             &         &          &          &\\
V1083 Oph (2) &       &47418.375     & 0.5523085     &             &         &          &          &40 \\
              &       &  $\pm$14     &   $\pm$25     &             &         &          &          &\\
V1083 Oph (3) &       &47418.380     & 0.5523132     & 5.0         &         &          &          &128 \\
              &       &  $\pm$12     &   $\pm$20     & $\pm$6      &         &          &          &\\
V1089 Oph     & RRab  &49475.521     & 0.6045402     &             & 13\fmm9 & 14\fmm9: & 0\fper16 &260 \\
              &       &   $\pm$5     &    $\pm$5     &             &         &          &          &\\
V1093 Oph     & RRab  &48830.443     & 0.4488517     &             & 15\fmm2 & 16\fmm5  & 0\fper18 &82 \\
              &       &  $\pm$10     &    $\pm$8     &             &         &          &          &\\
V1095 Oph (1) & RRab  &25864.342     & 0.4587875     &             & 14\fmm2 & 15\fmm8  & 0\fper23 &32 \\
              &       &   $\pm$7     &   $\pm$12     &             &         &          &          &\\
V1095 Oph (2) &       &47390.485     & 0.4587798     &             &         &          &          &195 \\
              &       &   $\pm$5     &    $\pm$6     &             &         &          &          &\\
V1095 Oph (3) &       &47390.485     & 0.4587778     & -1.8        &         &          &          &227 \\
              &       &   $\pm$5     &    $\pm$7     & $\pm$2      &         &          &          &\\

\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
    &  V1083 Oph           &     &  V1089 Oph          &\\
    &  S 9276           &     &  S 9862          & \\
    &  USNO 0900-11201195 &     &  USNO 0900-11607658& \\
\hline
Comp. No.  &  USNO      & m$^*$     & USNO      & m$^*$\\
\hline
1   &  0900-11206973 &  14\fmm8  & 0900-11599684 & 14\fmm0\\
2   &  0900-11199346 &  16\fmm2  & 0900-11610001 & 14\fmm7\\
3   &  0900-11197315 &  16\fmm4  & 0900-11600524 & 14\fmm7\\
4   &                &           & 0900-11604592 & 15\fmm2\\
\hline
%&&&&\\
&&&&\\
\hline
    & V1093 Oph           & & V1095 Oph &\\
    & S 9295             & & S 9868    &\\
    & USNO 0900-11721789 & & USNO 0900-11914415 & \\
\hline
Comp. No.  &  USNO     & m$^*$     & USNO     & m$^*$\\   
\hline
1   & 0900-11718573 & 15\fmm4&  0900-11926326 &  14\fmm1\\
2   & 0900-11722387 & 16\fmm0&  0900-11919647 &  14\fmm4\\
3   & 0900-11725709 & 16\fmm5&  0900-11909524 &  15\fmm3\\
4   &               &        &  0900-11909673 &  15\fmm5\\
\hline

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



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


\IBVS2fig{7cm}{5523-f1.eps}{Composite light curve of V1083 Oph}{5523-f2.eps}{(O$-$C) diagram for V1083 Oph\vspace*{-5cm}}
\IBVSfigKey{5523-f1.eps}{V1083 Oph}{light curve}
\IBVSfigKey{5523-f2.eps}{V1083 Oph}{O-C diagram}



\IBVS2fig{7cm}{5523-f3.eps}{Composite light curve of V1089 Oph}{5523-f4.eps}{(O$-$C) diagram for V1089 Oph}
\IBVSfigKey{5523-f3.eps}{V1089 Oph}{light curve}
\IBVSfigKey{5523-f4.eps}{V1089 Oph}{O-C diagram}



\IBVS2fig{7cm}{5523-f5.eps}{Light curve \mbox{(J.D. 2438258 $-$ 2449488)} of V1093 Oph }{5523-f6.eps}{(O$-$C) diagram for V1093 Oph\vspace*{-8cm}}
\IBVSfigKey{5523-f5.eps}{V1093 Oph}{light curve}
\IBVSfigKey{5523-f6.eps}{V1093 Oph}{O-C diagram}

\IBVS2fig{7cm}{5523-f7.eps}{Composite light curve of V1095 Oph}{5523-f8.eps}{(O$-$C) diagram for V1095 Oph}
\IBVSfigKey{5523-f7.eps}{V1095 Oph}{light curve}
\IBVSfigKey{5523-f8.eps}{V1095 Oph}{O-C diagram}


\clearpage

\begin{table}[!ht]
\centerline{\normalsize Table 3. Heliocentric times of new found maxima and $O-C$ values according to the elements derived in this paper}
%\small
\vskip 3mm
\begin{center}
\begin{tabular}{llrrllrr}
\hline
Star   &  JD (max.$^*$) &Epoch &$O-C$  &  Star   &  JD (max.$^*$) &Epoch &$O-C$  \\
\hline
V1083 Oph (1)&29787.418&$-$15338&0.022&V1093 Oph&38549.486&$-$22905&$-$0.009\\
&29788.477&$-$15336&$-$0.024&&38553.515&$-$22896&$-$0.020\\
&29845.389&$-$15233&0.003&&39611.517&$-$20539&0.039\\
&38258.415&0&$-$0.003&&39615.533&$-$20530&0.015\\
&38549.486&527&0.012&&39651.450&$-$20450&0.024\\
&39648.507&2517&$-$0.024&&39673.463&$-$20401&0.043\\
&39684.419&2582&$-$0.011&&39681.476&$-$20383&$-$0.023\\
&40418.435&3911&0.012&&39682.400&$-$20381&0.003\\
&40444.394&3958&0.013&&41160.461&$-$17088&$-$0.004\\
V1083 Oph (2)&45486.458&$-$3498&0.058&&45912.446&$-$6501&$-$0.012\\
&45492.490&$-$3487&0.015&&46272.443&$-$5699&0.006\\
&46533.612&$-$1602&0.035&&47387.432&$-$3215&0.047\\
&46642.386&$-$1405&0.004&&47392.361&$-$3204&0.039\\
&47387.432&$-$56&$-$0.014&&48830.441&0&$-$0.002\\
&47392.390&$-$47&$-$0.026&V1095 Oph (1)&25440.438&$-$924&0.016\\
&47418.344&0&$-$0.031&&25525.298&$-$739&0.000\\
V1089 Oph&25363.576&$-$39885&0.140&&25705.584&$-$346&$-$0.017\\
&25495.337&$-$39667&0.111&&25864.342&0&0.000\\
&25498.354&$-$39662&0.105&&29786.522&8549&0.006\\
&25707.563&$-$39316&0.143&&29787.445&8551&0.011\\
&26215.378&$-$38476&0.145&&29843.390&8673&$-$0.016\\
&29844.389&$-$32473&0.101&V1095 Oph (2)&39259.546&$-$17723&0.016\\
&38901.500&$-$17491&$-$0.009&&39270.525&$-$17699&$-$0.016\\
&40381.429&$-$15043&0.006&&39615.533&$-$16947&$-$0.010\\
&40384.439&$-$15038&$-$0.007&&39672.443&$-$16823&0.011\\
&40419.482&$-$14980&$-$0.027&&39711.401&$-$16738&$-$0.027\\
&40453.370&$-$14924&0.007&&40384.439&$-$15271&$-$0.019\\
&40473.320&$-$14891&0.007&&40418.435&$-$15197&0.027\\
&40803.395&$-$14345&0.003&&41163.465&$-$13573&$-$0.002\\
&41179.418&$-$13723&0.002&&44069.410&$-$7239&0.032\\
&45522.442&$-$6539&0.010&&46271.507&$-$2439&$-$0.014\\
&45912.382&$-$5894&0.021&&46272.443&$-$2437&0.004\\
&46288.406&$-$5272&0.021&&46509.637&$-$1920&0.009\\
&46291.399&$-$5267&$-$0.009&&46554.584&$-$1822&$-$0.005\\
&46506.628&$-$4911&0.004&&46731.243&$-$1437&0.024\\
&46509.637&$-$4906&$-$0.010&&47368.468&$-$48&0.004\\
&46552.594&$-$4835&0.025&&47380.392&$-$22&0.000\\
&47381.380&$-$3464&$-$0.013&&47385.422&$-$11&$-$0.017\\
&47387.432&$-$3454&$-$0.007&&47386.383&$-$9&0.027\\
&47390.470&$-$3449&0.008&&47390.470&0&$-$0.015\\
&48362.554&$-$1841&$-$0.008&&47391.382&2&$-$0.021\\
&49154.493&$-$531&$-$0.017&&47392.361&4&0.040\\
&49475.511&0&$-$0.010&&47770.344&828&$-$0.011\\
V1093 Oph&29788.511&$-$42424&0.153&&48832.396&3143&$-$0.035\\
\hline

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


\vspace*{-0.4cm}

\references

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

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

Savin, V. V., 1988a, {\it Perem. Zvezdy}, {\bf 22}, 746

Savin, V. V., 1988b, {\it Perem. Zvezdy}, {\bf 22}, 755

Surikov, O. G., 1982, {\it Perem. Zvezdy Priloz.}, {\bf 4}, 253

\endreferences

\IBVSedata{5523-t4.txt}
\IBVSdataKey{5523-t4.txt}{V1083 Oph}{photometry}
\IBVSedata{5523-t5.txt}
\IBVSdataKey{5523-t5.txt}{V1089 Oph}{photometry}
\IBVSedata{5523-t6.txt}
\IBVSdataKey{5523-t6.txt}{V1093 Oph}{photometry}
\IBVSedata{5523-t7.txt}
\IBVSdataKey{5523-t7.txt}{V1095 Oph}{photometry}

\end{document}

