\documentstyle[twoside]{article}

\input ibvs2.sty
\input ibvst.sty
\input epsf.sty

\begin{document}
\IBVShead{5299}{24 July 2002}

\IBVStitle{GSC 00279-00321: A New W UM\lowercase{a} Eclipsing Binary}

\IBVSauth{Koppelman, M. D.$^{1}$; Terrell, D.$^{2}$}

\IBVSinst{Starhouse Observatory, 1523 Valders Ave N, Golden Valley, MN USA,
e-mail: {\tt lolife@bitstream.net}}
\IBVSinst{Dept. of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 400, Boulder, CO 80302 USA, e-mail: {\tt terrell@boulder.swri.edu}}

\SIMBADobj{GSC 00279-00321}
\IBVStyp{ EW }
\IBVSkey{W UMa - TASS - photometry}
\IBVSabs{The TASS survey discovers a new W UMa variable star in Virgo.}


\begintext


\IBVSTnam{GSC 00279-00321}

\IBVSTcoo{11\hr57\mm51\fsec278}{06\deg27\arcm04\farcs70}{2000}

\IBVSTobs{M. Koppelman: Private observatory, MN USA, 160-mm Newtonian astrograph;\\
D. Terrell: Sommers Bausch Observatory, CO USA, 60-cm Boller and Chivens telescope;\\
T. Droege: Private Observatory TOM1, Batavia, IL, dual 100-mm refractors}

\IBVSTdet{M. Koppelman: SBIG ST-237A;\\
& D. Terrell: SBIG ST-8;\\
& T. Droege: Custom built dual CCD 442A}

\IBVSTfil{M. Koppelman: None;\\
& D. Terrell: Johnson V;\\
& T. Droege: Johnson V and Cousins I, Bessel formulation}

\IBVSTdateobs{2002.02.07, 2002.05.31, 2002.06.01, 2002.06.06}

\IBVSTcomp{GSC 00279-00536 GSC 00279-00287}

\IBVSTsysn

\IBVSTdata{Through IBVS Web-site as file 5299-t1.txt}
\IBVSedata{5299-t1.txt}

\IBVSTtyp{ EW }

\IBVSTrem{
The variability of GSC 00279-00321 was clearly demonstrated by data acquired from the TASS survey ({\it viz.} Droege, 2002; Henden, 2001) in February of 2002. The period and nature of the variability was not immediately apparent. Figure 1 shows the TASS V-band discovery observations and follow-up V-band observations by Terrell.
\vskip 0.5cm
Koppelman made extensive unfiltered observations to try to characterize the light curve. Figure 2 shows the characteristic shape of a W UMa binary. The system shows a large asymmetry of about 0.1 magnitudes between the maxima. The system may be associated with the X-ray source J115752.7+062658 as W UMa systems frequently show X-ray emission arising from coronal activity. Although our data are limited, there are indications that the system may exhibit light curve changes on time scales of weeks. 
\vskip 0.5cm
Using all of the available data, the period was determined by eye examination of phase plots at different trial values. Given the very limited temporal coverage of our observations, attempts to use more rigorous period-finding techniques were unsuccessful. A preliminary ephemeris for the brightness minimum is
\begin{equation}
\begin{array}{r@{}r@{}l}
2452425.7329 & {} + 0\fday2898 & {} \times E \\ 
\end{array}
\end{equation}
Coordinates are from the Tycho catalog, adjusted for proper motion by VizieR.
}

\IBVSTack{Many thanks are due to Tom Droege, Arne Henden, John Greaves and everyone else involved with The Amateur Sky Survey (TASS). This research made use of the SIMBAD database, operated by the CDS at Strasbourg, France.}

\references

Droege, T., 2000, {\it The Amateur Sky Survey (TASS)}, {\tt http://www.tass-survey.org/}

Henden, A. A., 2001, {\it JAAVSO}, {\bf 29}, 118, {\it ``The TASS Mark IV Photometric Survey''}

\endreferences


\IBVSfig{10cm}{5299-f1.eps}{TASS discovery (triangles) and Terrell follow-up (circles) V-band observations.}
\IBVSfig{10cm}{5299-f2.eps}{Koppelman unfiltered observations.}

\vfill\eject

\IBVSerratum{5278}

The epoch that was given for the new classical Cepheid NSV 02852 is the
time of maximum, so the ephemeris is:

$$HJD Max = 2452234.46 + 2.1371 \times E$$

\bigskip
\medskip

The correct reference of Cannon \& Pickering:

\medskip

\parindent=-1cm \leftskip 1cm

Cannon, A.J., and Pickering, E.C. 1918-1924, The Henry Draper Catalogue
and Extension, Ann. Astron. Obs. Harvard College, 91-100

\parindent=15.0pt \leftskip -0cm

\medskip

\noindent (Although HD252611 is in the Henry Draper Catalogue, it was actually
published in the HD catalogue extension.)

\bigskip
\bigskip

{\bf Enrique Garcia-Melendo}

\end{document}

