[Mesa-users] Issue with loaded donor star luminosity in binary
Kaz Harding
hardingk at myumanitoba.ca
Thu Jul 16 20:28:56 UTC 2026
Dear MESA users,
I am using the binary module in mesa-r26.04.1 to look at evolving mass transfer between a donor star and a point mass accretor.
The donor star is made from loading a saved model that I also created. This saved model is a rapidly accreting supermassive star in the early universe (see attached inlist: inlist_accretion). I stopped and saved the model (which is also attached) at a mass of 5000 solar masses, which had been accreting at a constant rate of 0.1 solar masses per year.
I then placed the star in a binary with a point mass, such that the Rochelobe of the system is located slightly outside the edge of the radius of the donor star (using the Eggleton formula, specifically so the Rochelobe was 1.05 times the radius of the donor star at the beginning). When I run the model, I immediately get issues with the luminosity equation. When graphed, the luminosity profile of the last step of the accretion run and the first step of the binary run are different, and there is a spike downward in the luminosity near the core boundary. This causes the system to only evolve for around 70 days before hitting the minimum timestep limit. I turned on debugging controls, and below I’ve included the solver progress near the end of the run:
max_residual > tol_max_residual 21 1.0521901485826320D-04 1.0000000000000000D-04
max_abs_correction > tol_max_correction*coeff 21 4.1913233393382392D-03 3.0000000000000001D-03 1.0000000000000000D+00
solver rejected trial model
s% model_number 21
s% solver_call_number 140
nz 4086
s% num_retries 1
dt 6.0492132168830186D+05
log dt/secyer -1.7174050747114848D+00
retry: max corr+resid -- give up in solver 21
solver_call_number 141
gold tolerances level 1
correction tolerances: norm, max 3.0000000000000001D-05 3.0000000000000001D-03
tol1 residual tolerances: norm, max 9.9999999999999994D-12 1.0000000000000001D-09
21 1 coeff 1.0000 avg resid 0.624E-03 max resid equL 3631 0.77769E+00 mix type 11111 avg corr 0.383E-04 max corr he4 3448 0.18379E-01 mix type 01111 avg+max corr+resid
21 2 coeff 1.0000 avg resid 0.504E-08 max resid equL 3446 0.10485E-03 mix type 00011 avg corr 0.455E-05 max corr lnd 3453 -0.14037E-02 mix type 11111 avg+max resid
21 3 coeff 1.0000 avg resid 0.988E-03 max resid equL 3454 0.12786E+01 mix type 11111 avg corr 0.440E-05 max corr lnd 3447 0.41810E-02 mix type 00111 max corr, avg+max resid
21 4 coeff 1.0000 avg resid 0.542E-08 max resid equL 3446 0.10520E-03 mix type 00011 avg corr 0.394E-05 max corr lnd 3447 -0.41887E-02 mix type 00111 max corr, avg+max resid
tol2 residual tolerances: norm, max 1.0000000000000000D-08 9.9999999999999995D-07
21 5 coeff 1.0000 avg resid 0.988E-03 max resid equL 3454 0.12786E+01 mix type 11111 avg corr 0.384E-05 max corr lnd 3447 0.41887E-02 mix type 00111 max corr, avg+max resid
21 6 coeff 1.0000 avg resid 0.542E-08 max resid equL 3446 0.10520E-03 mix type 00011 avg corr 0.385E-05 max corr lnd 3447 -0.41887E-02 mix type 00111 max corr+resid
21 7 coeff 1.0000 avg resid 0.988E-03 max resid equL 3454 0.12786E+01 mix type 11111 avg corr 0.385E-05 max corr lnd 3447 0.41887E-02 mix type 00111 max corr, avg+max resid
21 8 coeff 1.0000 avg resid 0.542E-08 max resid equL 3446 0.10520E-03 mix type 00011 avg corr 0.385E-05 max corr lnd 3447 -0.41887E-02 mix type 00111 max corr+resid
21 9 coeff 1.0000 avg resid 0.988E-03 max resid equL 3454 0.12786E+01 mix type 11111 avg corr 0.385E-05 max corr lnd 3447 0.41887E-02 mix type 00111 max corr, avg+max resid
tol3 residual tolerances: norm, max 9.9999999999999995D-07 1.0000000000000000D-04
21 10 coeff 1.0000 avg resid 0.542E-08 max resid equL 3446 0.10520E-03 mix type 00011 avg corr 0.385E-05 max corr lnd 3447 -0.41887E-02 mix type 00111 max corr+resid
21 11 coeff 1.0000 avg resid 0.988E-03 max resid equL 3454 0.12786E+01 mix type 11111 avg corr 0.385E-05 max corr lnd 3447 0.41887E-02 mix type 00111 max corr, avg+max resid
21 12 coeff 1.0000 avg resid 0.542E-08 max resid equL 3446 0.10520E-03 mix type 00011 avg corr 0.385E-05 max corr lnd 3447 -0.41887E-02 mix type 00111 max corr+resid
21 13 coeff 1.0000 avg resid 0.988E-03 max resid equL 3454 0.12786E+01 mix type 11111 avg corr 0.385E-05 max corr lnd 3447 0.41887E-02 mix type 00111 max corr, avg+max resid
21 14 coeff 1.0000 avg resid 0.542E-08 max resid equL 3446 0.10520E-03 mix type 00011 avg corr 0.385E-05 max corr lnd 3447 -0.41887E-02 mix type 00111 max corr+resid
21 15 coeff 1.0000 avg resid 0.988E-03 max resid equL 3454 0.12786E+01 mix type 11111 avg corr 0.385E-05 max corr lnd 3447 0.41887E-02 mix type 00111 max corr, avg+max resid
21 16 coeff 1.0000 avg resid 0.542E-08 max resid equL 3446 0.10520E-03 mix type 00011 avg corr 0.385E-05 max corr lnd 3447 -0.41887E-02 mix type 00111 max corr+resid
21 17 coeff 1.0000 avg resid 0.988E-03 max resid equL 3454 0.12786E+01 mix type 11111 avg corr 0.385E-05 max corr lnd 3447 0.41887E-02 mix type 00111 max corr, avg+max resid
21 18 coeff 1.0000 avg resid 0.542E-08 max resid equL 3446 0.10520E-03 mix type 00011 avg corr 0.385E-05 max corr lnd 3447 -0.41887E-02 mix type 00111 max corr+resid
21 19 coeff 1.0000 avg resid 0.988E-03 max resid equL 3454 0.12786E+01 mix type 11111 avg corr 0.385E-05 max corr lnd 3447 0.41887E-02 mix type 00111 max corr, avg+max resid
21 20 coeff 1.0000 avg resid 0.542E-08 max resid equL 3446 0.10520E-03 mix type 00011 avg corr 0.385E-05 max corr lnd 3447 -0.41887E-02 mix type 00111 max corr+resid
I also loaded the saved model into a constant mass loss regime in which the star evolves on its own with constant mass loss, and the luminosity equation/profile has no issues. To make sure that it wasn’t the mass transfer that was causing the issue, I increased the period so that the binary was essentially detached (mass loss of 1d-50), and the donor star started and evolved in the same way, and ended at the same age.
I’ve attached the inlist for the donor star (inlist1) and the binary (inlist_binary). I’ve also attached the luminosity profiles for the accreting model, and the binary model.
I am wondering if I am missing a control, or if there is a better way to load in the star, so that the luminosity profile will be consistent from the saved model to the loaded model? Any help anyone can provide would be greatly appreciated! Let me know if you need more information.
Kindest regards,
Kaz
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