The GYRE Forums

Dear Claudia -- Thanks for your question, and welcome to the forums. It appears that your FGONG model file has three points at the outer boundary with the same radial coordinate. This is what is causing the error. In reality, it's unlikely that the numerical model (MESA, right?) has this issue. Howe...

Hi Valentin, and welcome to the forums! These messages are completely normal; with recent updates to the SDK, the numerical behavior of GYRE changed a small amount (on the order of 1 part in 10^15), and that led to the error messages. They are a nuisance, and I'm figuring out how to make them go awa...

Peter --

You're absolutely right -- I can't imagine what I was thinking when I wrote my reply above. Positive Im(omega) will grow with time, and vice versa.

cheers,

Rich

Good question, Peter! Because Eulerian perturbations are fixed position, by definition r' = 0 and so delta r = xi_r

I am somewhat confused, trying to understand the oscillation equations completely. Many of them contain the term \omega_c. Is this the acoustical cutoff frequency for the model, or, as I think it might be in $GYRE_DIR/src/context/gyre_context.fpp, is it just the corotating frequency (which would th...

pjuelsgaard wrote: ↑

Tue Apr 26, 2022 2:16 am

Thanks for the detailed explanation. I was having a hard time wrapping my head around it.

Also, Günter Houdek sends his regards (he's my thesis advisor)

Glad I could help -- and do send regards back to Günter!

Hi Peter -- GYRE assumes a time dependence of exp(-i sigma t), where sigma is the mode angular frequency. Internally, GYRE works with the dimensionless frequency omega = sqrt(R^{3}/GM) sigma ...but the signs of sigma and omega agree. Modes with negative Im(sigma) are unstable and will grow with time...

I'd love to see stuff like this fixed, but I don't think it's worth doing until I've implemented some significant changes to how models are represented. Those changes will bring the ability to query which model data are valid.

Hi Peter --

The opacity partials given by MESA are typically defined as dkappa/dlnT etc, whereas GYRE uses dlnkappa/dlnT. Does that explain the difference?

cheers,

Rich

Warrick is right -- AMDL files don't contain sufficient information to perform non-adiabatic calculations. Unfortunately, this means (unless the AMDL format is extended) that models created by ASTEC cannot be used for non-adiabatic studies. By the way, c_thn and other coefficients are defined here: ...