\documentstyle[twoside,ibvs2,ibvst,ibvse,epsf]{article}

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\IBVShead{5558}{24 August 2004}

\IBVStitletl{New Variable Stars in the Open Cluster M35 (NGC 2168)}

\IBVSauth{Kim, H.-J.$^1$; Park, H.-S.$^1$; Kim, S.-L.$^2$; Jeon, Y.-B.$^2$; Lee, H.$^1$}

\IBVSinst{Department of Earth Science Education, Korea National Univ. of Education, Choongbuk 363-791, Korea; \\ email:leeho119@boao.re.kr}
\IBVSinst{Korea Astronomy Observatory, Daejon, 305-348, Korea}

\IBVSobj{V1 in NGC 2168}
\IBVSobj{V2 in NGC 2168}
\WEBDAobj{NGC 2168}
\IBVStyp{DSCT} % V1
\IBVStyp{E}    % V2
\IBVSkey{pulsation, photometry}

\IBVSabs{We report a detection of two new variable stars}
\IBVSabs{in the open cluster M35 (NGC2168).}


\begintext

\IBVSTobs{Mt. Lemmon Optical Astronomy Observatory in USA, 1.0m telescope}

\IBVSTdet{KODAK KAF-4301E 2048 CCD camera}

\IBVSTfil{Johnson $V$}

\IBVSTsys{yes}{Landolt (1992)'s SA 98}

\IBVSTdata{5558-t2.txt, 5558-t3.txt}

\IBVSedata{5558-t2.txt}
\IBVSdataKey{5558-t2.txt}{V1 in NGC 2168}{photometry}
\IBVSedata{5558-t3.txt}
\IBVSdataKey{5558-t3.txt}{V2 in NGC 2168}{photometry}


\IBVSEred{Standard CCD-frame reduction using the IRAF/DAOPHOT\footnotemark[1] package.}
\footnotetext[1]{IRAF is distributed by the National Optical Astronomy Observatories, which are operated by the Association of
Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.}

\begin{table}[h]
\centerline{{\bf Table 1.} Photometric parameters of observing stars from the WEBDA (Mermilliod, 1992)}
\begin{center}
\begin{tabular}{ccccccc}
\hline
\hline
\noalign{\smallskip}
ID$_{WEBDA}$  &  ID$_{OUR}$  &  RA (J2000) & DEC (J2000) & $V$ & $($B$-$V$)$ & $($V$-$I$)$ \\
\noalign{\smallskip} \hline \noalign{\smallskip}
3053 & V1    &  06\hr 08\mm 13\fsec22 & +24\deg 18\arcm 30\farcs8 & 16\fmm43 & 0\fmm64 & 0\fmm863 \\
3703 & V2    &  06\hr 09\mm 03\fsec31 & +24\deg 23\arcm 15\farcs6 & 17\fmm10 & 1\fmm30 & 1\fmm395 \\
272  & Comp  &  06\hr 08\mm 37\fsec36 & +24\deg 21\arcm 57\farcs5 & 14\fmm20 & 0\fmm96 & 1\fmm180 \\
241  & Check &  06\hr 08\mm 44\fsec30 & +24\deg 17\arcm 25\farcs2 & 14\fmm46 & 0\fmm40 & 0\fmm607 \\
\noalign{\smallskip} \hline \hline \noalign{\smallskip}
\end{tabular}
\end{center}
\end{table}

\IBVSEephem{V1 & 53071.755 & 0.0691 & present
paper \\
V2 & 53071.731 & 0.3639 & $ '' $ \\
}

\IBVSfig{10.0cm}{5558-f1.eps}{ The finding chart of the new variable
stars is presented in Fig. 1. New variables are labeled (V1) and
(V2) . The field is (14$\farcm$0$\times$9$\farcm$0), north is at
the top and east to the left. The chart is retrieved from the
STScI Digitized Sky Survey Second Generation Red. }
\IBVSfigKey{5558-f1.eps}{V1 in NGC 2168 ; V2 in NGC 2168}{finding chart}

\IBVSfig{8.5cm}{5558-f2.eps}{Phase diagram of V1}
\IBVSfigKey{5558-f2.eps}{V1 in NGC2168}{phased light curve}

\IBVSfig{8.5cm}{5558-f3.eps}{Phase diagram of V2}
\IBVSfigKey{5558-f3.eps}{V2 in NGC2168}{phased light curve}

\IBVSTrem{As a part of our survey project to searching for
low-amplitude pulsating stars in open clusters, we carried out
time-series CCD photometry for 2 nights March 7th to 8th\, 2004
in the open cluster M35 (NGC2168).
The observations were performed with the 1.0m telescope at Mt.~Lemmon
Optical Astronomy Observatory (LOAO), Arizona, USA; Korea
Astronomy Observatory has installed the telescope in September
2003. We examined light variation of 1128 stars
in the observed field and found two variable stars. 
One is a $\delta$ Sct type star and the other is a suspected eclipsing 
binary. We applied the ensemble
normalization technique (Gilliland \& Brown 1988, Kim et al. 1999)
to standardize the instrumental magnitudes of all stars in the
time-series CCD frames (for UBVI photometry of M53 see Sung and Bessell 1999). Finding chart of
these new pulsating stars is shown in Figure 1. Light curves are
displayed in Figure 2 and Figure 3.}


\references

Gilliland R.L., Brown T.M., 1988, {\it PASP}, {\bf 100}, 754

Kim, S.-L., Park, B.-G., Chun, M.-Y., 1999, {\it A\&A}, {\bf 348}, 795

Landolt, A.U., 1992, AJ, 104, 340

Mermilliod J.C., 1992, in ``Open cluster data base, BDA'' \\
({\tt http://obswww.unige.ch/webda})

Sung, H., Bessell, M.S., 1999, {\it MNRAS}, {\bf 306}, 361

\endreferences

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