Macrophysics Modules
These modules use the numerics and microphysics modules to implement various aspects of stellar structure and evolution.
MESA/ATM
MESA/MLT
MESA/COLORS
MESA/DIFFUSION
MESA/ATM
The MESA/ATM module provides routines to calculate conditions at the photosphere, either by interpolation in PHOENIX model atmosphere data, or by integrating various T(tau) relations.
MESA/MLT
The MESA/MLT module implements the mixing length theory of convection. The code closely parallels the description given in Chapter 14 of Cox and Giuli (1968) with an option for alternatively using the scheme of Henyey, Vardya, & Bodenheimer, 1965. There are options both for computing the actual temperature gradient as a function of a given luminosity, and also for computing the convective luminosity given a specified actual temperature gradient. In both cases, partial derivatives are computed as well as basic results.
There is also support for semiconvection and salt finger instability. Ledoux stability is calculated using a method derived from Heger, Woosley, & Spruit, 2005 (see eqn B2). In the case of salt finger instabilites, the diffusion coeffient is based on Kippenhahn, R., Ruschenplatt, G., & Thomas, 1980. For semiconvection, the diffusion coefficient is calculated following Heger, Langer, & Woosley, 2000 (see section 2.2.2).
References
John P. Cox and R. Thomas Giuli, Principles of Stellar Structure. 1968.
Henyey, Vardya, & Bodenheimer, 1965, ApJ, 142, 841.
Heger, Woosley, & Spruit, ApJ, 626:350-363, 2005.
Kippenhahn, R., Ruschenplatt, G., & Thomas, H.-C. 1980, A&A, 91, 175.
Heger, Langer, & Woosley, Apj, 528:368-396, 2000.
MESA/COLORS
The MESA/COLORS module implements a routine for calculating theoretical estimates of magnitudes and colors from Teff, L, M, and [Fe/H]. The color magnitude tables come from Lejeune, Cuisinier, and Buser.
Reference
T. Lejeune, F. Cuisinier, and R. Buser, “A standard stellar library for evolutionary synthesis: The M dwarf extension”, Astron. Astrphys. Suppl. Ser. 130, 65-75 (1998).
MESA/DIFFUSION
The MESA/DIFFUSION module handles gravitational settling and chemical and thermal diffusion. Radiative levitation is not currently supported. Burger’s equation is solved using a routine derived from Anne Thoul’s code. Approximate pressure ionization is based on Paquette et al. (as implemented in the MESA/IONIZATION package). The element diffusion equation is solved using a semi-implicit, finite difference scheme described by Iben and MacDonald.
References
Anne A. Thoul, John N. Bahcall, and Abraham Loeb, “Element Diffusion in the Solar Interior”, Ap.J. 421, 828-842 (1994)
Icko Iben and Jim MacDonald, “The Effects of Diffusion Due to Gravity and Due to Composition Gradients on the Rate of Hydrogen Burning in a Cooling Degenerate Dwarf. I. The Case of a Thick Helium Buffer Layer”, Ap.J. 296, 540-553 (1985)
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