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)=11.9, it increases in steps of 0.1 to lg(B)=15.0.
For lg(B)=13.5, there are two tables in different formats (I and II): in principle, both can be needed for interpolation in B (the first for interpolation at lg(B)<13.5, and the second for interpolation at lg(B)>13.5). 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.
The file name reflects lg(B) value: for instance, the file hmag12_5.dat contains the data for lg(B)=12.5

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. Every file is 217 Kbytes in size (ca. 60-70 Kbytes when gzipped) for lg(B)<13.5 and 125 Kbytes in size (ca. 35 Kbytes when gzipped) for lg(B)>13.5.

The whole set of 33 tables is available as a gzipped tar-archive (5.72 Mbytes; 1.65 Mbytes when gzipped). Use gzip -d hmagnet.tar.gz and tar xf hmagnet.tar 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) = 11.9 12.0 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 May 20, 2007.