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J/A+AS/123/273      Illumination in binaries  (Hameury+, 1997)
Illumination in binaries
      Hameury J.M., Ritter H.
      <Astron. Astrophys. Suppl. Ser. 123, 273 (1997)>
      =1997A&AS..123..273H      (SIMBAD/NED BibCode)
ADC_Keywords: Accretion

Keywords: accretion, accretion discs - stars: binaries: close - X-rays: stars -
          methods: numerical

Description:
    We give a simple, but accurate method that can be used to account for
    illumination in compact binary systems which have a low-mass
    companion, even if spherically symmetric illumination of the secondary
    star (not necessarily on the main sequence) is not assumed. This is
    done by introducing a multiplicative factor {PHI} in the
    Stefan-Boltzmann surface boundary condition, which accounts for the
    blocking of the intrinsic secondary flux by X-ray heating of the
    photospheric layers. Numerical fits and tables for {PHI} are given for
    unperturbed effective temperatures in the range 2500-5600K and logg in
    the range 1.0-5.0.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1            22   232875   Function G(x)
table2            52    10304   Coefficients of the fit of the modified
                                  Stefan-Boltzmann surface boundary condition.


Byte-by-byte Description of file: table1

   Bytes Format Units  Label      Explanations

   1-  4  F4.2 [cm/s2] logg       Surface gravity
   6-  9  F4.2  [K]    log(Teff)  Effective temperature of the unilluminated star
  11- 14  F4.2  ---    log(1+x)   log(1+x) where x is the illuminating flux in
                                 units of the unperturbed stellar flux
  16- 22  F7.5  ---  log(1/G(x))  -log(G(x)) where G is the fraction of the
                                 interior flux that is not blocked by
                                 illumination


Byte-by-byte Description of file: table2

   Bytes Format Units  Label     Explanations

   1-  3  F3.1  ---    R2/a      Ratio of the secondary radius versus
                                  orbital separation (f2=R2/a)
   5-  8  F4.2 [cm/s2] logg      Surface gravity
  10- 13  F4.2  [K]   log(Teff)  Effective temperature of the unilluminated star
  15- 26  E12.5 ---    a1        Coefficient a1 of the polynomial fit of the
                                  modified boundary condition
  28- 39  E12.5 ---    a2        Coefficient a2 of the polynomial fit of the
                                  modified boundary condition
  41- 52  E12.5 ---    a3        Coefficient a3 of the polynomial fit of the
                                  modified boundary condition


Acknowledgements: Jean Marie Hameury 

(End)                                         Patricia Bauer [CDS]   24-Sep-1996