[Mesa-users] cv

[Evan Bauer]

Hi Jason,

I've run across this bug in 15140 too. Other MESA versions should be fine. There was a naming collision with some experimental work on convective velocities that ended up causing cv not to be set for things like profile output. I believe this is a fairly minor bug, because all of the structure equations are written in terms of cp rather than cv, so this only affects the (optional) output of cv itself.

MESA should be able to give you enough output to reconstruct cv using the relation from Hansen, Kawaler, & Trimble eqn 3.90
cp - cv = (P/rho*T)*(chiT^2/chiRho)

All of the quantities in that equation besides cv should be available in MESA profile output. I hope that helps!

Cheers,
Evan

> On Feb 16, 2021, at 5:24 PM, Jason Wright via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> I'm having a strange bug trying to extract the specific heats from the profiles in MESA.
> 
> In my variables.list file for MESA I can include cp (constant pressure) but not cv.  I even copied the line directly from the defaults file to be sure I had it right (no special characters or anything).
> 
> When I comment it out, MESA runs fine and gives me c_p:
> cp
> !cv ! specific heat at constant volume
> 
> But when I uncomment that line I get this error:
> 
> failed to recognize item for profile columns: cv
> 
> I didn't see anything in the archives about this. Is there something special about cv? Can I hack it using other thermodynamic quantities?
> -- 
>                                                 - 
> ---------------
> Jason T Wright
> Professor of Astronomy & Astrophysics
> Director, Penn State Extraterrestrial Intelligence Center
> Acting Director, Center for Exoplanets and Habitable Worlds
> NEID Instrument Team Project Scientist <http://neid.psu.edu/>
> he/him/his
> https://sites.psu.edu/astrowright/ <https://sites.psu.edu/astrowright/>
> @Astro_Wright
> 
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