[Mesa-users] Adding a new thermal particle

[Josiah Schwab]

Hi Jeremy,

> Essentially, I want to add a new particle whose distribution is thermal, by
> which I mean I can compute the pressure, and entropy as a function of its
> mass (which I take as an input), and the density and temperature. The
> phenomena is similar to pair production in that I expect that the EOS will
> fall below 4/3 for some region of parameter space where the core
> temperature is near the particle's mass but not so high that the particle
> is relativistic.
>
> I can calculate the EOS directly using numerical integrals, or tabulate
> this if it is easier.
>
> My questions are:
>
> 1) What is the best way of accomplishing this?

Seems like you can get what you want by modifying the EOS, so I'd think
it is most straight forward to use the other_eos hook and have it call
the MESA eos and combine the results with your new EOS terms.

> 2) Will I see the dynamical instability that I see when I run the VMO
> test_suite if I implement it correctly?

I don't know what VMO means and am hesitant to make definite statements
about the future.  But people have used MESA to do pair-instability and
pulsational-pair instability supernovae, so I know MESA models can react
to a softening of the EOS.

Josiah