\documentstyle[twoside,epsf]{article}

\input{ibvs2.sty}

\begin{document}

\IBVShead{5171}{13 September 2001}

\IBVStitle{NSV 1012: a New Eclipsing Binary}

\IBVSauth{Berthold, Thomas$^{1,3}$; Verrot, Jean-Paul$^{2}$; Vandenbroere, Jacqueline$^{2}$;\\ \indent Martignoni, Massimiliano$^{1,2}$; Kroll, Peter$^{1,4}$}

\IBVSinst{Bundesdeutsche Arbeitsge\-mein\-schaft f\"{u}r
Ver\"{a}nderliche Sterne e.V. (BAV), Munsterdamm 90, \\ \indent
D--12169 Berlin, Germany}

\IBVSinst{Group Europ\'een d'Observations Stellaires (GEOS), 23 Parc de
Levesville, F--28300 Bailleau l'Ev\"{e}que, France,\\ \indent e-mail: j.vandenbroere@skynet.be, maxmartignoni@inwind.it, jp.verrot@wanadoo.fr}

\IBVSinst{Bruno-H.-B\"{u}rgel-Sternwarte Hartha, T\"{o}pelstr.\ 43,
D--04746 Hartha, Germany, e-mail: tb.stwhartha@web.de}

\IBVSinst{Sternwarte Sonneberg, Sternwartestr.\ 32, D--96515 Sonneberg,
Germany, e-mail: pk@stw.tu-ilmenau.de}

\SIMBADobjJ2000 {GSC 04317-00505}{03 02 20.71 +71 09 40.2}

\IBVStyp{ E } 

\IBVSkey{binaries: eclipsing}

\begintext

The variability of this star (GSC 4317 0505) was discovered by
Strohmeier (1959), who describes it as an eclipsing binary with light
changes ranging between photographic magnitudes 11\fmm0 to 11\fmm8. A
confirmation was published later by Strohmeier and Knigge (1961). This
information, together with the spectral type of A4, is listed in the
NSV catalogue (Kholopov 1982). Visual observations performed by Verrot
and Vandenbroere have yielded a first period of 2\fday273 (Verrot
2000). This value could be confirmed by photoelectric observations made
by Martignoni, but his measurements cover only a part of the light curve
without the ascending branch of the minimum. Observations on Sonneberg
Sky-Patrol plates (Berthold) were used to refine the elements with the
help of a long time base. Due to the very large number of plates
available for the region of NSV 1012, estimations were performed in
only two intervals of time. The first set includes 341 plates out of
the years 1962--1967 and a comparable number of plates out of the years
1981--1985 was searched for weakenings.

A least squares fitting of all available minima has yielded the
following linear ephemeris:
\begin {equation}
\begin{array}{r@{}r@{}l}
{\rm Min.\,I = HJD}~2451450.242 & {} + 2\fday2726178 & {} \times E. \\
{} \pm 0.007 & {} \pm 0.0000020 \\
\end{array}
\label{1}
\end {equation}

The corresponding photographic light curve is given in Figure 1. A
decision whether the given epoch in ephemeris (1) denotes the primary
or secondary minimum is still outstanding. Further CCD photometry is
urgently needed. Using blue magnitudes from the TYCHO2 catalogue for
the comparison stars in Table 1, NSV 01012 shows photographic light
changes within 11\fmm85 and 12\fmm90. The difference to the range of
variation reported by Strohmeier obviously results from a systematic
error in his comparison scale. The magnitudes derived from the
Sonneberg plates are well in agreement with the values given for the
uneclipsed star in some modern catalogues (USNO A2.0: 12\fmm1 pg;
TYCHO2: 11\fmm841 $B_T$).

Table 2 clearly points out the constancy of the period within the whole
investigated interval. Each of the photographic instants in this table
was derived only from a single sky-survey plate, so the scatter of the
$O-C$ values is comprehensible.

\begin{table}
\caption{Comparison stars}
\begin{center}
\begin{tabular}{ccc}
\hline
Designation & GSC & TYCHO2 $B$ mag \\
\hline
a & 4317 1077 & 11.11\\
b & 4317 0923 & 11.55\\
c & 4317 0913 & 11.89\\
d & 4317 0960 & 12.62\\
e & 4317 0671 & 12.95\\
\hline
\end{tabular}
\end{center}

\normalsize
\caption{Minima of NSV\ 1012 according to ephemeris (1)} 
\begin{center}
\begin{tabular}{clrl|crrl}
\hline
HJD 24\dots & \multicolumn1c{Epoch} & $O-C$ & Observer & HJD 24\dots & \multicolumn1c{Epoch} & $O-C$ & Observer \\
\hline
38856.540 & $-$5541.5 & 0.010 & Berthold & 39390.595 & $-$5306.5 & $-$0.001 & Berthold\\
38739.458 & $-$5593 & $-$0.033 & Berthold & 39499.678 & $-$5258.5 & $-$0.003 & Berthold\\
38530.480 & $-$5685 & 0.070 & Berthold & 45074.487 & $-$2805.5 & 0.074 & Berthold\\
38555.438 & $-$5674 & 0.029 & Berthold & 45223.312 & $-$2740\phantom{.5} & 0.043 & Berthold\\
38556.494 & $-$5673.5 & $-$0.051 & Berthold & 45407.310 & $-$2659\phantom{.5} & $-$0.041 & Berthold\\
38613.414 & $-$5648.5 & 0.054 & Berthold & 45583.467 & $-$2581.5 & $-$0.012 & Berthold\\
38622.410 & $-$5644.5 & $-$0.041 & Berthold & 45650.497 & $-$2552\phantom{.5} & $-$0.024 & Berthold\\
38638.390 & $-$5637.5 & 0.031 & Berthold & 45674.408 & $-$2541.5 & 0.024 & Berthold\\
38239.465 & $-$5813 & $-$0.050 & Berthold & 45907.390 & $-$2439\phantom{.5} & 0.063 & Berthold\\
38288.398 & $-$5791.5 & 0.022 & Berthold & 45940.349 & $-$2424.5 & 0.069 & Berthold\\
38322.385 & $-$5776.5 & $-$0.080 & Berthold & 45990.256 & $-$2402.5 & $-$0.022 & Berthold\\
38372.444 & $-$5754.5 & $-$0.019 & Berthold & 46200.460 & $-$2310\phantom{.5} & $-$0.035 & Berthold\\
38407.708 & $-$5739 & 0.020 & Berthold & 51185.482 & $-$116.5 & $-$0.000 & Vandenbroere\\
38413.403 & $-$5736.5 & 0.033 & Berthold & 51459.330 & 4\phantom{.5} & $-$0.003 & Verrot\\
38415.683 & $-$5735.5 & 0.040 & Berthold & 51460.418 & 4.5 & $-$0.051 & Verrot\\
38440.659 & $-$5724.5 & 0.018 & Berthold & 51492.295 & 18.5 & 0.010 & Verrot\\
38473.626 & $-$5710 & 0.032 & Berthold & 51509.306 & 26\phantom{.5} & $-$0.024 & Verrot\\
37939.575 & $-$5945 & 0.046 & Berthold & 51525.233 & 33\phantom{.5} & $-$0.006 & Verrot\\
37940.623 & $-$5944.5 & $-$0.042 & Berthold & 51550.247 & 44\phantom{.5} & 0.009 & Verrot\\
38089.474 & $-$5879 & $-$0.048 & Berthold & 51575.257 & 55\phantom{.5} & 0.021 & Verrot\\
38113.403 & $-$5868.5 & 0.019 & Berthold & 51576.334 & 55.5& $-$0.038 & Verrot\\
39023.533 & $-$5468 & $-$0.035 & Berthold & 51600.286 & 66\phantom{.5} & 0.052 & Verrot\\
39040.574 & $-$5460.5 & $-$0.039 & Berthold & 51601.346 & 66.5 & $-$0.026 & Verrot\\
39056.520 & $-$5453.5 & $-$0.001 & Berthold & 51609.323 & 70\phantom{.5} & $-$0.003 & Verrot\\
39088.256 & $-$5439.5 & $-$0.081 & Berthold & 51793.372 & 151\phantom{.5} & $-$0.035 & Verrot\\
39205.393 & $-$5388 & 0.016 & Berthold & 51842.279 & 172.5 & 0.010 & Verrot\\
39256.472 & $-$5365.5 & $-$0.039 & Berthold & 51908.236 & 201.5 & 0.062 & Verrot\\
39289.443 & $-$5351 & $-$0.021 & Berthold & 51934.313 & 213\phantom{.5} & 0.003 & Verrot\\
39355.398 & $-$5322 & 0.028 & Berthold & 51951.290 & 220.5 & $-$0.064 & Verrot\\
39380.371 & $-$5311 & 0.002 & Berthold & 51984.322 & 235\phantom{.5} & 0.014 & Verrot\\
39388.372 & $-$5307.5 & 0.049 & Berthold & & & \\
\hline
\end{tabular}
\end{center}
\end{table}

\clearpage

\IBVSfig{8cm}{5171-f1.ps}{Photographic light curve of NSV 1012. The dots refer to sliding means
($N=3$) of the individual estimates}

\references 

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

Kholopov, P.N., editor, 1982, New Catalogue of Suspected Variable Stars, Moscow 

Monet, D., et al., 1998, The USNO Catalogue,\\ {\tt http://ftp.nofs.navy.mil/projects/pmm/catalogs.html}

Strohmeier W., 1959, {\it Bamb.\ Ver.}, {\bf 5}, No.\ 3

Strohmeier W., Knigge, W., 1961, {\it Bamb.\ Ver.}, {\bf 5}, No.\ 10

Verrot, J.P., 2000, {\it GEOS NC}, {\bf 919}

\end{document}
