## Input Physics

Here we describe the physics associated with the input parameters used in MESA. For a more in-depth review of these parameters please see Paper I, Paper II, or more recently Paper III.

**Control Parameters**

__Nuclear Reaction Network__A net is defined by a set of isotopes and a set of reactions.

Descriptions of some of the nuclear reaction networks provided by the README with mesa/data/net_data/nets/.

for "no frills" hydrogen and helium burning

**-- h1, he3, he4, c12, n14, o16, ne20, mg24**

*basic*assumes T is low enough so can ignore advanced burning and hot cno issues.

the following nets provide more complete coverage for hydrogen and helium burning

**--**

*hot_cno***+ c13, n13, n15, o15, o17, o18, f17, f18**

*basic*for high temperatures where cno becomes beta limited.

**--**

*cno_extras***+ o14, f19, ne18, ne19, mg22**

*hot_cno*for high temperatures where start to breakout of hot cno.

**--**

*pp_and_cno_extras***+**

*pp_extras*

*cno_extras*

__Mixing__

*Mixing Length Alpha**l = α H*,

_{p}where

*l*is the mixing length, α is a free parameter, and

*H*is the pressure scale height.

_{p}

*Mixing Length Theory Implementation*-

**- Gives radiative values with no mixing.**

*none*-

**- MLT as developed in Cox & Giuli 1968, Chapter 14.**

*Cox*-

**- Bohm-Vitense 1958.**

*ML1*-

**- Bohm and Cassinelli 1971.**

*ML2*-

**- Mihalas 1978, Kurucz 1979.**

*Mihalas*-

**- Henyey, Vardya, and Bodenheimer 1965.**

*Henyey*

*Convective Overshoot*The overshooting diffusion coefficient

*D*is given by

_{OV}*D*=

_{OV}*D*exp(

_{conv,0}*-2z/f*),

_{OV}λ_{P,0}where

*D*is the convective diffusion coefficient measured a distance f

_{conv,0}_{OV,0}inside the convective zone,

*z*is the radial distance and λ

_{P,0}is the local pressure scale height. Overshooting then extends beyond the edge of the convective zone a distance f

_{OV}. Both f

_{OV,0}and f

_{OV}are assumed to be given as fractions of the local pressure scale height.

__Winds__

*RGB/AGB Wind Eta*Mass loss efficiency, varies with wind scheme.

*Wind Scheme*-

**- D. Reimers, Baschek, Kegel, Traving (eds), Springer, Berlin, 1975, p. 229.**

*Reimers*-

**- T. Blocker A&A 297, 727-738 (1995).**

*Blocker*-

**- Kudritzki et al, Astron. Astrophys. 219, 205-218 (1989).**

*Kudritzki*-

**- Nieuwenhuijzen, H.; de Jager, C. 1990, A&A, 231, 134.**

*Nieuwenhuijzen*-

**- Vink, J.S., de Koter, A., & Lamers, H.J.G.L.M., 2001, A&A, 369, 574.**

*Vink*-

**- Grafener, G. & Hamann, W.-R. 2008, A&A 482, 945.**

*Grafener*-

**- Glebbeek, E., et al, A&A 497, 255-264 (2009).**

*Dutch*

__Rotation__

*Initial Rotation*Rotational value is set at the zero-age main sequence as a fraciton of the critical angular velocity given by

*Ω*,

^{2}_{crit}= (1-L/L_{edd})GM/R^{3}where

*L*is the luminosity,

*L*the Eddington luminosity,

_{edd}*G*the universal gravitational constant,

*M*the stellar mass, and

*R*the stellar radius.