J/AcA/56/253  Period changes of OGLE contact binaries  (Kubiak+, 2006)
Period changes of contact binaries in OGLE database.
    Kubiak M., Udalski A., Szymanski M.K.
   <Acta Astron., 56, 253-265 (2006)>
   =2006AcA....56..253K 2006AcA....56..253K
ADC_Keywords: Binaries, eclipsing ; Photometry
Keywords: binaries: close - binaries: eclipsing
Abstract:
    Presented are results of determination of secular period changes for
    569 contact binaries from the OGLE database with periods shorter than
    about one day and observations spanning 14 observing seasons. The
    statistically significant rates of secular changes found for 134 stars
    are distributed nearly symmetrically around zero with a half-width of
    the distribution equal to about 3.5x10-7d/yr. The remaining rates
    are confined within the error distribution with dispersion about
    2.3x10-7d/yr. The largest rates of period change that have been
    found are of the order of 5x10-6d/yr.
File Summary:
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 FileName  Lrecl  Records   Explanations
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ReadMe        80        .   This file
table1.dat    61      679   Contact binaries in OGLE database used for
                             determination of secular period changes
table2.dat    64      569   Time derivatives of periods determined by the
                             method of variance minimization
table3.dat    52      272   Results of the "average O-C diagram" method
lc/*           .      569   Individual light curves
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See also:
           I/244 : OGLE General Catalog of Stars. I. (Szymanski+ 1996)
          II/213 : OGLE Galactic Bulge periodic variables (Udalski+ 1996)
           V/119 : Catalogue of field contact binary stars (Pribulla+, 2003)
           V/120 : Catalog of early-type contact binaries (Bondarenko+, 1996)
  J/A+A/426/1001 : Catalog of contact binary stars (Csizmadia+, 2004)
    J/AcA/51/259 : Contact binaries in OGLE-I database (Szymanski+, 2001)
Byte-by-byte Description of file: table1.dat
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   Bytes Format Units   Label     Explanations
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   1-  4  A4    ---     Field     Field
   6- 11  I6    ---     Star      Star number in the field
  14- 21  F8.6  d       Per       Period
  25- 29  F5.2  mag     Imag      Observed brightness in I band
  32- 35  F4.2  mag     V-I       ?=9.99 Observed V-I colour index
  39- 40  I2    h       RAh       Right ascension (J2000)
  42- 43  I2    min     RAm       Right ascension (J2000)
  45- 49  F5.2  s       RAs       Right ascension (J2000)
      51  A1    ---     DE-       Declination sign (J2000)
  52- 53  I2    deg     DEd       Declination (J2000)
  55- 56  I2    arcmin  DEm       Declination (J2000)
  58- 61  F4.1  arcsec  DEs       Declination (J2000)
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Byte-by-byte Description of file: table2.dat
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   Bytes Format Units   Label     Explanations
--------------------------------------------------------------------------------
   1-  4  A4    ---     Field     Field
   6- 11  I6    ---     Star      Star number in the field
  13- 21  F9.7  d       P         Best value of the period
  24- 32  E9.4  d/yr    dP/dt     Rate of period change
  35- 38  I4    ---     Nobs      Number of observations
  40- 44  F5.3  ---     Fst       F-statistics
  46- 51  F6.1  ---     Pst       P-statistics
  54- 64  A11   ---     FileName  Name of the light curve in "lc" subdirectory
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Byte-by-byte Description of file: table3.dat
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   Bytes Format Units   Label     Explanations
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   1-  4  A4    ---     Field     Field
   6- 11  I6    ---     Star      Star number in the field
  14- 21  F8.6  d       P         Period
  25- 28  I4    ---     Nobs      Number of observations
  32- 40  E9.4  d/yr    dP/dt     Rate of period change determined from the
                                   quadratic term in the O -C diagram
  45- 52  E8.4  d/yr    p.e.      Formal error of the solution
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Byte-by-byte Description of file: lc/*
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   Bytes Format Units   Label        Explanations
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   3- 12  F10.5 d       HJD-2448000  Heliocentric Julian date, HJD-2448000
  16- 21  F6.3  mag     dImag        I-band brightness minus mean
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History:
    Copied at ftp://ftp.astrouw.edu.pl/acta/2006/kub_253
(End)                                      Patricia Vannier [CDS]    08-Jun-2007