[mesa-users] Z=0.04 and MESA r9793

[Philip D. H. <pdh...@gm...>]

Hello,

I want to use MESA r9793 to evolve a 1.3Msol, Y=0.32, Z=0.04 star from the
zero age main sequence. I find strange behaviour near the base of the giant
branch for this high metallicity star: a jump in L and Teff, as shown in
the attached HR diagram (z0.04...pdf, red track, jump between the crosses).
The same model evolved with r8845 (black track) does not show this jump.

I assume this is related to changes to the opacity and/or equation of
state, but I haven't been able to solve it. Do you have any ideas?

Initial model and inlist for r9793 attached. The initial model is a
homogenous 1.3Msol, Y=0.32, Z=0.04 ZAMS star.

The other plot (z0.02...pdf) compares 1.3Msol, Y=0.28, Z=0.02 models
evolved with r8845 and r9793. The tracks lie on top of each other.

Thanks,

Philip D. Hall
Armagh Observatory