Polytropic Stars


Astronomy research
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   Stellar equation of states
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   1D PPM Hydrodynamics
   Verification problems
   Plane - Cube Intersection


   Zingale's software
   Brown's dStar
   GR1D code
   Iliadis' STARLIB database
   Herwig's NuGRID
   Meyer's NetNuc
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Contact: F.X.Timmes
my one page vitae,
full vitae,
research statement, and
teaching statement.

The code contained in public_poly.tbz computes the structure of stars that are in hydrostatic equilibrium and obey a polytropic equation of state. The code solves the dimensionless Lane-Emden equation and writes out a solution in physical units. Certain polytropic stars are related cold white dwarfs.

image Various pathways in the PV-plane for a polytropic equation of state. Note that gamma = 1/n + 1 = n when n is equal to the golden ratio.
image Numerical solutions to the Lane-Emden equation. For n < 5, the solutions can be continued to negative y. Although not physical, such solutions exists mathematically, and are quite useful for determining the values of x and dy/dx when y is zero. It's an exercise for the user to compare the computed surface values with other's tabulated values.
image Difference between the analytical and numerical solutions for n = 0, 1, and 5 for various integration accuracies.
image The larger n, the more extended the object. Other physical properties can be plotted from the generated output files.
image It was a good day. Chicago. 2nd floor LASR.

Please cite the relevant references if you publish a piece of work that use these codes, pieces of these codes, or modified versions of them. Offer co-authorship as appropriate.