MESAHub / MESAHub/mesa

Omega glitch after remeshing

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#1,047 9 comments 0 reactions 1 assignee Claimed by @matthiasfabry View on GitHub
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Description

I've been doing some tests with red giant models including rotation (right now using the default settings, so only accounting for conservation of angular momentum) and I'm seeing some glitches that I think are introduced by remeshing.

To illustrate, here are some Omega profiles in the core region of a somewhat evolved red giant (log g ~3):
Image

As you can see, this region gets remeshed after model number 1545 and then Omega exhibits a glitch for every model after this point. If I run these same models with `okay_to_remesh = .false.` then this glitch never develops.

Image

This, (as well as the fact that in the remeshed models the inner zone seems to overestimate Omega whereas the outer zone seems to underestimate it) suggests to me that there's some issue with how the angular momentum is getting distributed when the model is remeshed.

Here's a work dir with a starting model right before this glitch develops for ease of replication:
[rotation_mesh_test.zip](https://github.com/user-attachments/files/31415651/rotation_mesh_test.zip)

Version information:
- MESA version: 26.04.1
- MESA SDK VERSION: mesasdk-x86_64-linux-26.3.2
- OS: Ubuntu 24.04.4 LTS

Any insight would be much appreciated!

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