NSG Home Page EOS and effective opacities for magnetic neutron stars
Tables and interpolating program
Neutron Star Group
[Magnetic H EOS Main page] [Go to the data]

Description

The equation of state (EOS) and opacities of hydrogen are tabulated along isotherms.

Input parameters:

The lowest value of the magnetic field is lg(B)=10.5, it increases in steps to lg(B)=15.0.
The tables for different values of T and B have identical structure. They are concatenated one after another for all values of T at every fixed value of B. (Note that these files have 2 header lines for lg(B) < 11.9 but 5 header lines for other B values).
The file name reflects lg(B) value: for instance, the file hmag12_5.dat contains the data for lg(B)=12.5; the file hmm11a8.dat contains the data for lg(B)=11.845. (Two files with names hmm10a8.dat and hmm11a8.dat correspond to lg(B)=10.845 and 11.845, respectively.)

Every table consists of 14 columns, which give different physical quantities.

The first line contains decimal logarithms (log10=lg) of T and B.

Each row then provides:

  1. lg(R)
    astrophysical density parameter: density rho [g/cm3] is given by R*T63
  2. lg(P)
    P is the pressure in bar = 106 dyn/cm2
  3. PV/(NkT)
    dimensionless pressure parameter: N is the constant total number of protons (free and bound) in the volume V, k is the Boltzmann constant; P = PV/(NkT)*rho*T6*8.250E+13 dyn/cm2
  4. U/(NkT)
    dimensionless energy parameter: U is the internal energy, the zero point of energy is the quantum-mechanical continuum; energy per gram [erg/g] is given by U/(NkT)*T6*8.250E+13
  5. S/(Nk)
    dimensionless entropy parameter: S is the entropy; entropy per gram [erg/g/K] is given by S/(Nk)*8.250E+07
  6. CV/(Nk)
    reduced heat capacity:
    CV is the heat capacity at constant volume; CV in [erg/g/K] is given by CV/(Nk)*8.250E+07
  7. chit = (d log P/d log T)_V
    logarithmic derivative of P with respect to T at constant volume
  8. chir = (d log P/d log rho)_T
    logarithmic derivative of P with respect to density at constant T
  9. x(H)
    the atomic fraction:
    the total number of H atoms with non-destroyed energy levels divided by N
  10. x(H0)
    the ground-state atomic fraction: the number of ground-state H atoms divided by N
  11. x(H2)
    the molecular fraction: the number of H2 molecules with non-destroyed levels divided by N
  12. x(pert.)
    the fraction of protons comprised in clusters and strongly perturbed atoms and molecules
  13. lg(K0)
    K0 is the effective Rosseland mean opacity [cm2/g] for radiative transport along B
  14. lg(K1)
    K1 is the Rosseland mean opacity [cm2/g] for radiative transport perpendicular to B
Any second-order thermodynamic function can be obtained by combination of (3)-(8). For example, the heat capacity at constant pressure equals CP = CV + (PV/T)*chit2/chir, the adiabatic gradient equals ( d log P / d log T )_S = chit/[chit2+chir*(CV/Nk)/(PV/NkT)].
The effective Rosseland mean opacity for radiative transport at arbitrary angle theta to the magnetic field can be obtained as 1/K = (1/K0)*(cos theta)2 + (1/K1)*(sin theta)2.

The tables for different T are concatenated in a file for every specific B value. These files are compressed with gzip. Before using, unzip them: employ gzip -d *.gz or gunzip *.gz (on Unix/Linux platforms; or an appropriate analogue if you use another operating system). Alternatively, your browser may be set to unzip the files automatically during download.

The whole set of tables is available as a gzipped tar-archive (∼ 2 Mb). (For instance, in Linux, use tar xf hmagnet.tar.gz to retrieve all the tables.)

We also provide a Fortran program for quick interpolation across the tables.

Please communicate us your opinion about this resource or send any suggestions or remarks.

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Download:
README README (the above description of files)
Button Tables (gzipped): lg(B) = 10.5 10.6 10.7 10.845 11.0 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.845 11.9 12.0(I) 12.0(II) 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 13.0 13.1 13.2 13.3 13.4 13.5(I) 13.5(II) 13.6 13.7 13.8 13.9 14.0 14.1 14.2 14.3 14.4 14.5 14.6 14.7 14.8 14.9 15.0
entire archive The whole set of tables (gzipped tar-archive)
Interpolating code Fortran program for interpolation across the tables

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[Top of this page] [Magnetic H EOS Main page] [Neutron Star Group] [Department of Theoretical Astrophysics] [Ioffe Institute]

Page design and maintenance by Alexander Potekhin (palex@astro.ioffe.ru). Remarks are always welcome.
Page created on May 30, 2002. last updated on October 19, 2014.