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\IBVShead{5009}{29 December 2000}
\IBVStitle{V807 C\lowercase{as} is an Eclipsing Binary Star}
\IBVSauth{Garcia-Melendo, E.$^1$; Henden, Arne A.$^2$}

\IBVSinst{Esteve Duran Observatory, Montseny 46 -- Urb.\ El Montanya,
08553 Seva, Spain\\ \indent e-mail: duranobs@astrogea.org}

\IBVSinst{USRA/USNO, P.O. Box 1149, Flagstaff, AZ 86002--1149, USA, e-mail: aah@nofs.navy.mil}

\SIMBADobj{V807 Cas}

\begintext

\IBVSTnam{V807 Cas = HIP 114552 = GSC 4010\_285}

\IBVSTcoo{23\hr12\mm13\fsec0}{+59\deg35\arcm59\farcs2}{2000.0}

\IBVSTobs{Esteve Duran Observatory, 0.6-m Cassegrain telescope;\\
US Naval Observatory Flagstaff Station, 1.0-m Ritchey--Chr\'etien telescope}

\IBVSTdet{CCD in both cases}

\IBVSTfil{$B$, $V$, $R_c$, $I_c$}

\IBVSTcomp{GSC 4010\_463}

\IBVSfig{6.25cm}{5009-f1.eps}

\IBVSTchk{GSC 4010\_1201}

\IBVSTsys{Johnson--Cousins}{Landolt standards (Landolt, 1992)}

\IBVSTdata{Upon request}

\IBVSTtyp{ EB }

\IBVSTrem{
V807 Cas was discovered as a variable star by the Hipparcos mission
(ESA, 1997). It was classified as a periodic variable with a
0\fday97463 period, a mean $V$ magnitude of 10\fmm79, and an average
$B-V=0\fmm340$ without specifying variability type. V807 Cas is in the
center of PK110--0.1, which was initially classified as the planetary
nebula We~1--12. Recent spectroscopic data by Kimeswenger (1998)
indicate that V807 Cas has a B1V spectral type, and that We~1--12 is
not a planetary nebula but an isolated H II region, as was also
suggested by earlier works (e.g.\  Zijlstra et al.\ 1990; Kaler and
Feibelman 1985).  Kimeswenger also claims that V807 Cas is the only
source of excitation of the H II cloud.\\
Our analysis of the satellite data suggested that V807 Cas was actually
an EB eclipsing binary star with a period close to twice the one given
in the Hipparcos catalogue. To investigate further about the variable
nature of V807 Cas, this object was observed in a collaborative program
between Esteve Duran Observatory and the U.S. Naval Observatory
Flagstaff Station. This star was monitored in the $V$ band for 17
nights, from July to September 1997. Table~1 (available electronically
through IBVS Web-site as 5009-t1.txt) lists the standard $V$ magnitudes
and color indices of field stars near the variable.\\
Observations show that V807 Cas is in fact an EB eclipsing binary
system with a period close to two days (Figure~1). The phased light
curve presents a primary minimum with a depth of 0.18 magnitudes, and a
secondary minimum during which the star fades 0.11 magnitudes. At
maximum light, V807 Cas has a $V$ magnitude of $10.80\pm0.01$. It was
also found an average $B-V=0.319\pm0.003$. After combining our data
with HIPPARCOS photometry the following ephemeris was computed:
$$\begin{array}{r@{}r@{}l}
{\rm Min.~I = HJD}~2450652.428 & {} + 1\fday949189 & \times E. \\
                     \pm 0.006 &      \pm 0.000015 \\
\end{array}$$
If V807 Cas is actually the source of excitation of PK110--0.1,
additional photometric and spectroscopic data might help to solve the
system, and obtain a more precise measurement of the H~II region
distance and its properties.}

\IBVSedata{5009-t1.txt}

\IBVSTack{This work made use of the SIMBAD data base, operated at CDS,
Strasbourg, France.}

\references

ESA, 1997, The Hipparcos and Tycho Catalogues, ESA SP-1200

Kaler, J. B., Feibelman, W. A., 1985, {\it PASP}, {\bf 97}, 660

Kimeswenger, S., 1998, {\it MNRAS}, {\bf 294}, 312

Landolt, A. U., 1992, {\it AJ}, {\bf 104}, 340

Zijlstra, A., Pottasch, S., Bignell, C., 1990, {\it A\&AS}, {\bf 82}, 273

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