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J/A+A/403/637       V and R light curves of GSC 3822-1056    (Csizmadia+, 2003)
Photometric Study of the Over-Contact Binary Star GSC 3822-1056.
    Csizmadia Sz., Biro I>B>, Borkovits T.
   <Astron. Astrophys. 403, 637 (2003)>
   =2003A&A...403..637C
ADC_Keywords: Binaries, eclipsing ; Photometry, UBV ; Photometry, Cousins

Keywords: techniques: photometric - stars: binaries: eclipsing -
          stars: binaries: close - stars: individual: GSC 3822-1056

Abstract:
    Here we present the first Johnson-Cousins VRC light curves of the
    over-contact binary star GSC 3822-1056. A period study and the light
    curve solution are also given. An extremely high rate of period
    increase +11.6sec/century was found. The origin of this period change
    can be: (i) partly covered light-time effect due to the orbital motion
    around the mass center of a possible third body; (ii) mass transfer
    between the components. The light curve was solved by the 1998
    Wilson-Devinney Code. We examined the light curve with and without
    third light. Both solutions yielded a contact configuration with high
    temperature difference between the components. Despite the high degree
    of the contact (f=0.57), the temperature difference between the
    components ΔT=Tprimary-Tsecondary=1045K. The high mass-ratio
    of the system and its other unusual properties suggest that GSC
    3822-1056 may be a recently formed contact binary.

Description:
    The object we studied were observed with a Wright Instruments
    1024x1024 CCD camera mounted on the 80 cm "IAC80" telescope at
    Observatorio del Teide in Tenerife, Spain, operated by Instituto de
    Astrofisica de Canarias using Johnson-Cousins V and RC filters.
    Typical integration times were 20s for V and 10s for RC bands
    respectively. 2x2-pixel binning was used to obtain an optimal
    sampling of the star profiles of FWHM nearly equal to 3 pixels, and
    only a subframe of size 3x7 arcminutes, containing DW UMa and the two
    comparison candidates GSC 3822-1056 (which is actually a W UMa-type
    variable and our study is on this star) and GSC 3822-0070. In this way
    the time between frames was shortened to 5 seconds.
Objects:
    ----------------------------------------------------------
       RA   (2000)   DE      Designation(s)
    ----------------------------------------------------------
    10 33 57.8   +58 52 16   GSC 3822-1056
    10 33 48.9   +58 52 31   GSC 3822-0070
    ----------------------------------------------------------

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table2a.dat       20      271   GSC 3822-1056 Johnson V light curve
table2b.dat       20      244   GSC 3822-1056 Cousins R light curve
table2c.dat       30     1091   GSC 3822-1056 relative magnitude to GSC 3822-0070


Byte-by-byte Description of file: table2a.dat

   Bytes Format Units   Label     Explanations

   1- 13  F13.5 d       HJD       Heliocentric Julian date
  15- 20  F6.3  mag     Vmag      Johnson V magnitude of GSC 3822-1056


Byte-by-byte Description of file: table2b.dat

   Bytes Format Units   Label     Explanations

   1- 13  F13.5 d       HJD       Heliocentric Julian date
  15- 20  F6.3  mag     Rmag      Cousins R magnitude of GSC 3822-1056


Byte-by-byte Description of file: table2c.dat

   Bytes Format Units   Label     Explanations

   1- 13  F13.5 d       HJD       Heliocentric Julian date
  17- 22  F6.3  mag     Dmag      Unfiltered magnitude of GSC 3822-1056
                                   relative to GSC 3822-0070
  26- 30  F5.3  mag     e_Dmag    Scatter of measurement of Dmag


Acknowledgements: Szilard Csizmadia 

(End)                                         Patricia Bauer [CDS]   15-Apr-2003