A simple yet powerful tool for solving numerically, the fundamental equations of stellar structure. It uses the Runge-Kutta fourth order method (commonly known as RK4) to express the mass, density and pressure as a function of the star's radius.
Throughout this program the following assumptions were made
- Spherical symmetry. So the value of any function at a specific point, depends only in its distance from the center of the star.
- The star is isolated in space.
- The star is in a state of hydrostatic equilibrium.
A comprehensive list of the equations solved and the constants that are required to run the program, can be found [here] (https://www.dropbox.com/s/ilaf5tz9b2flfkv/equations.pdf?dl=0). In regards to density, the star was modeled as a polytrope. Polytropes are self-gravitating gaseous spheres that are very useful as crude approximation to more realistic stellar models. A detailed discussion on polytropes can be found [in this document] (http://www.astro.princeton.edu/~gk/A403/polytrop.pdf "Polytropes").
From the /stellar-structure directory (wherever you decide to place it) compile with
make
To use the program, edit the boundaryConditions.txt file with the data of a main sequence star of your choice. Then run
./stellarStructure
The provided boundaryConditions.txt has the data of the Sun.
The program generates three ".dat" files, one for each funtion (mass, density, pressure). The file has two columns in the form
| Radius | Function |
You can see a plot of a typical output [here] (https://www.dropbox.com/s/69w10ssrumwlnhx/typicalOutput.pdf?dl=0 "Typical Output").
- Add the radiative transfer equation
- Add more functions (such as temperature, luminosity, etc.)
MIT