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\IBVShead{4131}{28 December 1994}                      % Use it with dummy or empty arguments

% Call for macro \title {Title of the paper}
\title{WW~Cephei: Elements rediscovered and improved}
\vskip -9mm
\centerline{[BAV Mitteilungen Nr. 71]}
\vskip 8mm

% Call for macro \begintext
\begintext

The  Algol--type eclipsing binary  WW~Cep = 241.1928 Cephei
was discovered by Schnel\-ler (1928) on photographic plates of Babelsberg
Observatory. Later, Schneller (1931) published a list of individual photographic
magnitudes ranging between 11\fmm \hspace{-1ex}.\,0 and
11\fmm \hspace{-1ex}.\,8, determined the time between first and last contact of the primary
minimum as D = 4\fh \hspace{-1ex}.\,1 and reported the following 
first elements:
\[ {\rm Min\, I = HJD}\,2425098.527 \, + \, 4\fdd \hspace{-1ex}.\,60086\times\rm E.\]

Metzger rediscovered the variable independently on the same photographic plates
and found D= 0\fdd \hspace{-1ex}.\,15 and d= 0\fdd \hspace{-1ex}.\,03
(Staker, 1931).
WW~Cep was again investigated by G\"{o}tz (1951) on plates of the Sonneberg Sky
Survey. He submitted four minima timings and calculated new elements:
\[ {\rm Min\, I = HJD}\,2425029.495 \, + \, 1\fdd \hspace{-1ex}.\,53360\times\rm E.\]

With these elements WW~Cep is listed in the GCVS (1985). \v{S}ilh\'{a}n (1982)
reported that in a photographic and visual search the primary minimum could
not be found. Lacy (1990) noted that his spectrograms are inconsistent
with the ephemeris listed in the GCVS (1985). Photoelectric photometry by Lacy
(1992) showed no sign of an eclipse at phase 0.0327. Using the
photographic magnitudes published by Schneller (1931) together with the
elements from the GCVS, a reduction to one cycle shows that seven measurements
contradict the ephemeris used. In spite of all that,  two BBSAG
observers published 17 visual minima which follow quite well the published
elements. These discrepancies made WW~Cep a candidate for the observing
program of the author.

The observations were made at his private observatory with an SBIG ST6
CCD--camera without filters attached to a 20 cm SC--telescope. WW Cep was
observed on 20 nights between Apr.~1993 and Oct.~1994.
The rather large scatter in the lightcurve is due to not always photometric
weather conditions. The minima times were calculated using the
Kwee~--~van Woerden (1956) method. From about two and a half thousand pictures
over almost all phases the true period could be rediscovered. It is very near
the original one suggested by Schneller.
In the instrumental system the depth of the primary and secondary minima were
found to be 0\fmm \hspace{-1ex}.\,64 and  0\fmm \hspace{-1ex}.\,16, respectively.

Using the minima from Parenago and Schneller together with
the new observations, a least squares fit yields the following linear
ephemeris. The visual observations by the BBSAG seem to be affected by
systematic error and had to be excluded.
\arraycolsep0mm
\begin{equation}
  \begin{array}{r}  {\rm  Min\,  I = HJD}\,2449662.4438 \\
  \pm 2 \end{array}
  \begin{array}{r}
   \, + \,\, 4\fdd \hspace{-1ex}.\,60084540 \\
     \pm 14 \end{array}
  \begin{array}{r}\,\times\rm\, E\\
      { }
     \end{array}
\label{1}
\end{equation}

\vfill \eject
\centerline{2}


\epsfysize=6cm
\centerline{\epsffile{4131-f1.ps}}
\centerline{Figure 1: Differential light curve of WW~Cep computed}
\centerline{with respect to the new ephemeris (1).}

\vskip 2mm
\epsfysize=6cm
\centerline{\epsffile{4131-f2.ps}}
\centerline{Figure 2: O--C--diagram for WW~Cep computed with respect to}
\centerline{the new ephemeris (1) using all available minima timings.}
\centerline{$\bullet$ represents  photoelectric, $\circ$ photographic series,}
\centerline{+ visual observations and {\raisebox{0.3ex}{$_\Box$}} photographic plate minima.}

\vskip 2mm
\epsfysize=6cm
\centerline{\epsffile{4131-f3.ps}}
\centerline{Figure 3: O--C diagram for WW~Cep computed with respect to}
\centerline{the new ephemeris (1) using only photoelectric observations.}
\vskip 20mm
\vfill \eject

\centerline{3}
\vskip 1mm
\centerline{Table 1. Observed times of minima for WW~Cep, epochs and residuals}
\centerline{computed with respect to the ephemeris (1) derived in this paper.}
\vskip 1mm
\begin{center}
\footnotesize
\begin{tabular}{rr@{.}lrlr@{.}lr@{.}lc||rr@{.}lrlr@{.}lr@{.}lc}
\hline 
 N & \multicolumn{2}{c}{JD hel.} & W & T$^*$ &
 \multicolumn{2}{c}{Epoch} &
 \multicolumn{2}{l}{(O--C)} & Lit &
 N & \multicolumn{2}{c}{JD hel.} & W & T$^*$ &
 \multicolumn{2}{c}{Epoch} &
 \multicolumn{2}{l}{(O--C)} & Lit \\
  & \multicolumn{2}{c}{2400000+} & & &
 \multicolumn{2}{c}{} &
 \multicolumn{2}{l}{} & &
  & \multicolumn{2}{c}{2400000+} & & &
 \multicolumn{2}{c}{} &
 \multicolumn{2}{l}{} & \\
\hline
   1 & 16375 & 36  &  2 &   P   &   $-$7235 & 0 &  +0 &  03   & [1]  & 20 & 47757 & 392 &  0 &   V:: &    $-$414 & 0 &   --0 &  302  & [11] \\
   2 & 25029 & 518 &  2 &   P   &   $-$5354 & 0 &  +0 &  000  & [2]  & 21 & 48125 & 455 &  0 &   V:: &    $-$334 & 0 &   --0 &  306  & [12] \\
   3 & 25098 & 526 & 20 &   F   &   $-$5339 & 0 &   --0 &  004  & [2]  & 22 & 48444 & 452 &  0 &   V:: &    $-$265 & 5 &   --1 &  068  & [13] \\
   4 & 25121 & 530 &  2 &   P   &   $-$5334 & 0 &   --0 &  004  & [2]  & 23 & 48467 & 451 &  0 &   V:: &    $-$260 & 5 &   --1 &  073  & [13] \\
   5 & 25503 & 400 &  1 &   P:  &   $-$5251 & 0 &   --0 &  005  & [2]  & 24 & 48490 & 456 &  0 &   V:: &    $-$255 & 5 &   --1 &  073  & [13] \\
   6 & 25908 & 280 &  1 &   P:  &   $-$5163 & 0 &  +0 &  001  & [2]  & 25 & 48619 & 267 &  0 &   V:: &    $-$227 & 5 &   --1 &  085  & [14] \\
   7 & 32119 & 308 &  0 &   P:: &   $-$3813 & 0 &   --0 &  112  & [3]  & 26 & 48852 & 363 &  0 &   V:: &    $-$176 & 0 &   --0 &  332  & [15] \\
   8 & 32292 & 554 &  0 &   P:: &   $-$3776 & 5 &  +0 &  602  & [3]  & 27 & 49217 & 394 &  0 &   V:: &     $-$97 & 5 &   --1 &  068  & [16] \\
   9 & 33134 & 551 &  0 &   P:: &   $-$3593 & 5 &  +0 &  644  & [3]  & 28 & 49218 & 4690& 60 &   E   &     $-$97 & 5 &  +0 &  0068 & [17] \\
  10 & 33151 & 454 &  0 &   P:: &   $-$3589 & 5 &   --0 &  856  & [3]  & 29 & 49220 & 435 &  0 &   V:: &     $-$96 & 0 &   --0 &  328  & [16] \\
  11 & 43509 & 335 &  0 &   V:: &   $-$1338 & 5 &  +0 &  522  & [4]  & 30 & 49563 & 5213& 60 &   E   &     $-$22 & 5 &   --0 &  0043 & [17] \\
  12 & 45932 & 434 &  0 &   V:: &    $-$811 & 5 &   --1 &  025  & [5]  & 31 & 49586 & 5283& 60 &   E   &     $-$17 & 5 &   --0 &  0016 & [17] \\
  13 & 46320 & 404 &  0 &   V:: &    $-$727 & 5 &  +0 &  474  & [6]  & 32 & 49593 & 427 & 30 &   E:  &     $-$15 & 0 &   --0 &  004  & [17] \\
  14 & 47116 & 329 &  0 &   V:: &    $-$554 & 5 &  +0 &  453  & [7]  & 33 & 49600 & 328 & 30 &   E:  &     $-$14 & 5 &   --0 &  004  & [17] \\
  15 & 47323 & 387 &  0 &   V:: &    $-$509 & 5 &  +0 &  473  & [8]  & 34 & 49625 & 6366& 60 &   E   &      $-$8 & 0 &   --0 &  0004 & [17] \\
  16 & 47392 & 381 &  0 &   V:: &    $-$494 & 5 &  +0 &  454  & [9]  & 35 & 49632 & 5410& 60 &   E   &      $-$7 & 5 &  +0 &  0027 & [17] \\
  17 & 47412 & 324 &  0 &   V:: &    $-$489 & 0 &   --0 &  306  & [10] & 36 & 49639 & 4405& 60 &   E   &      $-$5 & 0 &+0 &  0009 & [17] \\
  18 & 47415 & 390 &  0 &   V:: &    $-$489 & 5 &  +0 &  459  & [9]  & 37 & 49646 & 3424& 60 &   E   &      $-$4 & 5 &  +0 &  0016 & [17] \\
  19 & 47737 & 432 &  0 &   V:: &    $-$419 & 5 &  +0 &  442  & [11] & 38 & 49662 & 4427& 60 &   E   &       0 & 0 &   --0 &  0011 & [17] \\
\hline
\end{tabular}
\end{center}

\vskip 1mm
\footnotesize
[1]: Parenago (1934),
[2]: Schneller (1931),
[3]: G\"{o}tz (1951),
[4]: Peter (1978),
[5]: Peter (1984),
[6]: Peter (1985),
[7]: Peter (1988a),
[8]: Bl\"{a}ttler (1988),
[9]: Peter (1988b),
[10]: Bl\"{a}ttler (1989),
[11]: Peter (1989),
[12]: Peter (1990),
[13]: Peter (1991),
[14]: Peter (1992a),
[15]: Peter (1992b),
[16]: Peter (1994),
[17]: this paper\\
$^*)$ P\, denotes pg plate min., E\, CCD min., F\, pg series
and V\, visual estimates. Those marked with \lq :\rq\ got reduced weight while
those marked with \lq ::\rq\ were discarded.

\large

\vskip 5mm
It should be mentioned that plate E409 at epoch 2425505.468 (m = 11.13) of the
list of photographic magnitudes by Schneller (1931), if
significant, seems to indicate the descend to a secondary minimum. If this is
true, the phase of min II would have been at phase 0.46 whereas the new
measurements show min II at phase 0.5. Therefore WW~Cep may be a system 
with apsidal motion.

\vspace{1cm}

% Call for macros \authors - \authorsrightcol - \endauthors
\beginauthors
\authorsrightcol
F.~AGERER
{\small Bundesdeutsche Arbeitsgemeinschaft
        f\"{u}r Ver\"{a}nderliche Sterne e.V. (BAV)
        Zweikirchen, Dorfstrasse 19,
        D-84184 Tiefenbach, Germany}
\endauthors

% Call for macro \references
\references

 Bl\"{a}ttler, E.: 1988, {\it BBSAG Bull.}, 89,

 Bl\"{a}ttler, E.: 1989 {\it BBSAG Bull.}, 90,

 G\"{o}tz, W.: 1951, {\it Mitt. Ver. Sterne}, 135

 Kholopov  P.N.  et  al.: 1985, Gen. Cat. of Var. Stars, $4^{\rm th}$\
Ed., Nauka, Moscow

 Kwee, K.K., van Woerden, H.: 1956, {\it Bull. Astr. Inst. Netherlands}, {\bf 12},
327

 Lacy, C.~H.: 1990, {\it Inf. Bull. Var. Stars}, No.\,3448

 Lacy, C.~H.: 1992, {\it Astr. Journal}, {\bf 104}, 801

 Parenago, P.: 1934, {\it Perem. Zvezdy}, {\bf 4}, 351

 Peter, H.: 1978, {\it BBSAG Bull.}, 36

 Peter, H.: 1984, {\it BBSAG Bull.}, 73

 Peter, H.: 1985, {\it BBSAG Bull.}, 78

 Peter, H.: 1988a, {\it BBSAG Bull.}, 86
\vfill 
\eject

\centerline{4}
\vskip 4mm

 Peter, H.: 1988b, {\it BBSAG Bull.}, 89

 Peter, H.: 1989, {\it BBSAG Bull.}, 92

 Peter, H.: 1990, {\it BBSAG Bull.}, 96

 Peter, H.: 1991, {\it BBSAG Bull.}, 98

 Peter, H.: 1992a, {\it BBSAG Bull.}, 100

 Peter, H.: 1992b, {\it BBSAG Bull.}, 102

 Peter, H.: 1994, {\it BBSAG Bull.}, 105

 Schneller, H.: 1928, {\it Astr. Nachrichten}, No.\,5571

 Schneller, H.: 1931, {\it Ver. Berlin-Babelsberg}, {\bf 8}, 6.29

 \v{S}ilh\'{a}n, J.: 1982, {\it Contr. N. Copernicus Obs. and Plan. Brno}, {\bf 23}, 26

 Staker, P.: 1931, {\it Astr. Nachrichten}, No.\,5828

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