[Mesa-users] Variable Physical Constants in the evolution of stars to white dwarfs

[Josiah Schwab]

Hi Raj,

I am interested in adapting MESA to include variable physical constants
> (VPC) defined as follows:
> G=G_0f(t)^3, c=c_0f(t), h=h_0f(t), and k_B=k_B0f(t)^1.25 leading to
> Gdot/G=3cdot/c, etc., with f(t) given in a functional or numerical form
> over the life of the universe. We want to determine the evolution of a star
> into white dwarf and determine its age under the VPC approach (MNRAS 2020,
> 498, 4481).  Please advise if it can be done.
>

Picking a time variable G is simple.  MESA has an other_cgrav hook that
allows you to modify G at runtime in essentially arbitrary ways.

Self-consistently varying kB, c, and h is practically impossible. You could
change the constants in const_def, but a MESA model also depends on all
sorts of microphysics data (equation of state, opacities, nuclear reaction
rates and Q values).  Those won't be recalculated on the fly with varying
constants and I think in many cases the dependence is too complex to let
you incorporate the effect via some simple scaling.

Josiah
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