Neutron Stars for Undergraduates

With Sanjay Reddy, also of T-16, I presented a paper with this title at the January 2003 Meeting of the Association of American Physics Teachers (Austin Texas). The PowerPoint presentation (in zipped format, PowerPoint 95, 78 KB) is available for you to read now. We submitted a paper with this title to the American Journal of Physics, and it was published in Vol. 72, 892-905 (2004).

The originally submitted version is available for download from

Here are the associated Mathematica and MathCad files that go with that talk and paper.

Mathcad Files

MathCad is a Windows application. The following Zip archive (27 KB) contains three files,

NewtonianStar, case of polytropic power = 5/3.

FermiGasEoS, for a charge-neutral mixture of neutrons, protons, and electrons in weak interaction equilibrium.

PureNeutronStar, for the Fermi Gas EoS giving energy density as a fitted function of pressure.

These should work with the Standard version of MathCad, Version 7, and higher.

Mathematica Notebooks

These should work with Mathematica, Version 4, and higher, independent of platform. (Windows, Mac, Linux, Sun, and other versions of Mathematica that may exist). Clicking on these links gives you the notebook in ASCII format, which can be copied onto your hard drive and then opened in Mathematica.

WhiteDwarf53.nb, Newtonian white dwarf (least massive cases) with polytropic power = 5/3, (53 KB).

WhiteDwarf43.nb, White dwarf (maximum mass cases) with polytropic power = 4/3, (53 KB).

FermiEoSneutron.nb, Tabulation and fitting of a pure neutron Fermi gas Equation of State. Gives pressure as a function of energy density for a range of Fermi momenta from non-relativistic to relativistic, (105 KB).

PureNstarFullFermiEoS.nb, Neutron star with full Fermi gas equation of state, (141 KB), illustrating the size of the General Relativistic corrections to a Newtonian calculation.

PrakashEoS.nb, Equation of state for a simple model of nuclear matter following Prakash, (220 KB).

PureNstarPrakashEoS.nb, Neutron star with the Prakash nuclear equation of state, (132 KB).

FermiEoSnpe.nb, Equation of State for a neutron star with small admixtures of protons and electrons, (111 KB).

All of the above Mathematica files can also be downloaded in a gzipped tar file (184 KB).