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| Polytropic Stars |
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The code given below computes the structure of stars that are in hydrostatic equilibrium and obey a polytropic equation of state. That is, it solves the dimensionless Lane-Emden equation and puts the physical units back in. Certain polytropic stars are related cold white dwarfs.
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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. |
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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. |
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Difference between the analytical and numerical solutions for n = 0, 1, and 5 for various integration accuracies. |
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The larger n, the more extended the object. Many other physical properties can be plotted from the output files that are generated. |
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poly2.f plus two include files: implno.dek const.dek |