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Contact:
F.X.Timmes, my vitae
Before using the routines below, you should glance at the web pages that describe them: "The Accuracy, Consistency, and Speed of Five Equations of State for Stellar Hydrodynamics", and "The Accuracy, Consistency, and Speed Of An Electron-Positron Equation Of State Based On Table Interpolation Of The Helmholtz Free Energy".
Pressure comparison |
Exact solution comparison |
Thermodynamic Consistency |
Here are bzip2 tarballs of six stellar interior equations of state:
| helmholtz.tbz | nadyozhin.tbz | iben.tbz |
| weaver.tbz | arnett.tbz | timmes.tbz |
Comments: The Helmholtz EOS executes the fastest, displays perfect thermodynamic consistency, has a maximum error of 1e-6, and is the stellar EOS of choice in the FLASH code. The Helmholtz free energy data file for this EOS spans 10-12 ≤ density (g cm-3) ≤ 1015 and 103 ≤ temperature (K) ≤ 1013.
The Nadyozhin EOS is the fastest of the analytic routines, has very good thermodynamic consistency, a maximum error of 1e-5, and is avaliable in the FLASH code.
The Timmes EOS is as slow as molasses during a North Dakota winter, but it computes the non-interacting electron-positron equation of state with no approximations, is exact to machine precision in IEEE double precision arithmetic, has excellent thermodynamic consistency, and serves as the reference point for comparisons to the other EOS routines. In fact, the Helmholtz free energy table for the Helmholtz EOS was calculated from the Timmes EOS.