Failing to blend EOS around Z=0.04 #921
Description
When diffusion is turned on and Z drops below 0.04, the EOS changes. This leads to discontinuities in the star's evolution.
This was found while running a ~0.65 Msun model at Z a little larger than 0.04 with do_element_diffusion = .true.
Setting OPAL_SCVH = .false. removes this discontinuity.
Below is surf_cell_z vs. logTeff for model grid of a ~0.65 Msun star on the main sequence. Note that when surf_cell_z crosses 0.04, there is a sharp change in logTeff.
Version
- MESA version [r24.08.1]
- MESA SDK VERSION [aarch64-macos-25.8.1.pkg)]
- OS: [MacOS 15.6.1]