CDROM/AJ/V109/P0359      H235 in NGC 752 (Milone+ 1995)
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Observations and Analysis of the Contact Binary H235 in the Open Cluster NGC 752
      E. F. Milone, C. R. Stagg, B. A. Sugars, J. R. McVean, S. J. Schiller,
      J. Kallrath & D. H. Bradstreet
      <1995, AJ, 109, 359>
      =1995AJ....109..359M
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Abstract:
  The short-period variable star Heinemann 235 in the open cluster NGC
  752 has been identified as a contact binary with a variable period of
  about 0.4118 d.  BVRI light curves and radial velocity curves have been
  obtained and analyzed with enhanced versions of the Wilson-Devinney
  light curve program.  We find that the system is best modeled as an
  A-type W UMa system, with a contact parameter of 0.21 +/- 0.11.  The
  masses of the components are found to be 1.18 +/- 0.17 and 0.24 +/-
  0.04 Msun, with bolometric magnitudes of 3.60 +/- 0.10 and 5.21 +/-
  0.13, for the hotter (6500 K, assumed) and cooler (6421 K) components,
  respectively, with Delta T = 79 +/- 25 K.  The distance to the binary
  is established at 381 +/- 17 pc.  H235 becomes one of a relatively
  small number of open-cluster contact systems with detailed light curve
  analysis for which an age may be estimated.  If it is coeval with the
  cluster, and with the detached eclipsing and double-lined spectroscopic
  binary H219 (DS And), H235 is ~1.8 Gyr old, and may provide a fiducial
  point for the evolution of contact systems.  There is, however,
  evidence for dynamical evolution of the cluster and the likelihood of
  weak interactions over the age of the binary precludes the
  determination of its initial state with certainty.


File Summary:
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File Name    Lrecl    Records   Explanations
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table3.dat      78        867   Photoelectric light curve data
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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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   1-10   F10.4  d        HJD        Heliocentric Julian Date - 2400000
  11-18   F8.4   ---      Ph1       *Phase of minima from ephemeris 1
  19-26   F8.4   ---      Ph3       *Phase of minima from ephemeris 3
  27-33   F7.3   mag      dV         Differential V magnitude
  34-40   F7.3   mag      dB         Differential B magnitude
  41-47   F7.3   mag      dR         Differential R magnitude
  48-54   F7.3   mag      dI         Differential I magnitude
  55-62   F8.3   mag      d(B-V)     Differential (B-V) color
  63-70   F8.3   mag      d(V-R)     Differential (V-R) color
  71-78   F8.3   mag      d(V-I)     Differential (V-I) color
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Notes for file: table3.dat
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Ph1:
  Phase of minima calculated using ephemeris (1) from printed paper:
        E0 = 2 447 815.338(3), P = 0.411 83(12)d

Ph3:
  Phase of minima calculated using ephemeris (3) from printed paper:
        E0 = 2 446 785.8660(23), P = 0.411 775 0(10)d
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(End)                                             Lee Brotzman [ADS] 29-Apr-1995