TYCHO: physics sources

Microscopic physics derived from:

Opacity

At temperatures above about 10,000K the opacitiy is that of Rogers and Iglesias 1996 ApJ 464, 943. (See also The OPAL Opacity Code, and The Opacity Project) For lower temperature, the opacity is smoothly interpolated to tables from David Alexander; these opacities are formulated for several different compositions. See also Alexander, D. R. & Ferguson, J. W. 1994, ApJ, 437, 879, Low-temperature Rosseland opacities.

TYCHO chooses the appropriate metallicity and interpolates between tables for different hydrogen nucleon fractions at the given metallicity at each timestep.

Reaction Networks

Nuclear reaction networks: Arnett, D., Supernovae and Nucleosynthesis, 1996, Princeton University Press

Thermonuclear reaction rates

Nuclear reaction rates: Basel astrophysics. NACRE, Rauscher and Thielemann, and Iliadis, C., D'Auria, J., Starrfield, S., Thompson, W., and Wiescher, M., 2001, ApJS, 134, 151.

Equation of State

Equation of state: Helmholtz Free energy formulation, See Timmes and Arnett 1999 ApJS 125, 277, and Timmes and Swesty 2000 ApJS 126, 501 .

For coulomb effects, Rogers, Swenson, Iglesias 1996 ApJ 456, 902, and work in progress.

Gravitational Settling by Diffusion

See John Bahcall's website for the Thoul subroutine, based on Thoul, A. A., Bahcall, J. N., Loeb, A., 1994, ApJ, 421, 828.

Return to main TYCHO page. E-mail:darnett@as.arizona.edu