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\input ibvs2.sty
\input ibvst.sty

\begin{document}

\IBVShead{5624}{8 April 2005}

\IBVStitletl{The First CCD BVRI Light Curves}{ of the Near-Contact Binary V387 C\lowercase{yg}}

\IBVSauth{Manimanis, V. N.; Niarchos, P. G.}

\IBVSinsto{Dept. of Astrophysics, Astronomy and Mechanics, Faculty of Physics, National \& Kapodistrian University of Athens, Athens, Greece; e-mail: vmaniman@cc.uoa.gr}


\SIMBADobj{V387 Cyg}
\IBVSabs{Complete BVRI light curves of eclipsing binary V387 Cyg show a large}
\IBVSabs{asymmetry after the secondary minimum, indicative possibly of a hot}
\IBVSabs{and a cool spot (although there is no observable O' Connell effect).}
\IBVSabs{Since a period increase is also detected, there is strong evidence of}
\IBVSabs{mass transfer.}


\begintext

\IBVSTnam{V387 Cyg, TYC 2714-556-1}

\IBVSTcoo{21\hr 15\mm 37\fsec4}{+37\deg 29\arcm 52\arcs}{2000}

\IBVSTobs{National Observatory of Athens Kryonerion Station, 1.22 m Cassegrain telescope}

\IBVSTdet{PMIS CCD camera, Peltier \& water cooled, 528 $\times$ 528 pixels binned to 264 $\times$ 264, 2.5\arcm \ $\times$ 2.5\arcm \ FOV.}

\IBVSTfil{BVRI}

\IBVSTdateobs{2004.05.12, 2004.05.13, 2004.06.28, 2004.06.29, 2004.06.30}

\IBVSTcomp{GSC 02714-00043}

\IBVSTchk{Uncatalogued fainter star 25\arcs \hspace{1mm} SSW of the comparison}

\IBVSTsysn

\IBVSTdata{Available upon request}

\IBVSTtyp{ EB }

\IBVSTrem{Three minima times were obtained, indicating period increase. The heights of the two maxima are equal in all bands, i.e. no O' Connell effect is present. However, a strong asymmetry of the light curve after $MinII$ is apparent, which is pronounced in $B$ and $V$, but minimal to nonexistent in the $R$ and $I$ curves. The surface temperature of the members of this binary is low, theoretically allowing the presence of cool spots. Moreover, the large difference in the depths of minima suggests large surface temperature difference and, thus, a semi-detached configuration for the system. This fact and the evidence for period changes suggest episodes of mass transfer between the members. Indeed, a hot spot radiating at shorter wavelengths would explain the shoulder of the curves after $MinII$, followed by the effect of a cool spot best visible at phase 0.65, which again decreases light emitted at shorter wavelengths. However, this cool spot should contribute to at least a small O' Connell effect for phase 0.75.}

\IBVSTack{This research was included in the {\it PYTHAGORAS} project for the support of research groups in the universities, co-funded by the EPEAEK program and the European Social Fund (ESF).}

\IBVSfig{12cm}{5624-f1.eps}{The complete $BVRI$ light curves of V387 Cyg}
\IBVSfigKey{5624-f1.eps}{V387 Cyg}{light curve}

\IBVSedata{5624-t1.txt}
\IBVSedata{5624-t2.txt}

\end{document}
