[Mesa-users] Custom weak rate

[Francis Timmes]

hi guo,

there is not a lot to go on here. while mesa indicates it read your custom rate, the results suggest the rate is not being used. perhaps follow 

https://docs.mesastar.org/en/latest/net/nets.html#inspect-the-temperature-dependence-of-used-rates

to see if mesa is in fact caching the rate, and that the cached rate has the correct values.

fxt





> On Jul 21, 2025, at 11:59 PM, Guo Li via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> Hi all
> Let me add some more content.
> 
> dy163 β⁻ decay to ho163 is not included in the JINA database.
> I performed the same calculation in MESA-24.8.1 and checked the β⁻ decay rate of dy163.The program calculates it as a constant value, independent of temperature and YeRho!
> 
> Best regards,  
> Guo Li  
> 
> 
> At 2025-07-21 17:46:53, "Guo Li via Mesa-users" <mesa-users at lists.mesastar.org> wrote:
> 
> Hi all
> I am writing to seek clarification regarding anomalous results in my AGB star s-process nucleosynthesis simulations using MESA-r12778. I encountered unexpected behavior with the decay of Dy-163 that contradicts theoretical expectations, and I would appreciate your expertise in diagnosing the issue.
> Simulation Setup
> Model: 2M☉ star with metallicity Z = 0.01
> Physics Focus: s-process nucleosynthesis during thermally pulsing AGB phase
> Custom Weak Rate: Implemented the dy163_wk-minus_ho163 rate from literature via an HDF5 table (attached).
> MESA confirmed successful loading: reading user weak rate file: /home/liguo/MESA/.../weak_rates_dy163_ho163_right_length.h5  
> Observed Anomaly
> He-flash Convective Zone (TP-AGB phase)
> Temperature: ~3×10⁸ K
> log(ρYₑ) (lYeRho): ≲ 3.5
> Result: Minimal Dy-163 decay (negligible Ho-163 production)
> Convective Envelope
> Temperature: < 10⁶ K
> log(ρYₑ): < -5
> Result: Excessive Dy-163 decay → Abnormally high Ho-163 abundance
> This contradicts literature , where Dy-163 is expected to decay efficiently in high-temperature He-burning zones (T ≳ 2×10⁸ K).
> Could the issue be caused by insufficient coverage of T9s and lYeRho ranges in my HDF5 weak-rate table? I extended the ranges to both lower temperatures and broader/extremes of lYeRho (larger and smaller values), yet the results remain unchanged.
> Attachments
> HDF5 weak-rate table
> profile.data during a thermal pulse (illustrating T, lYₑRho, and abundances)
> I would be grateful for any insights into resolving this discrepancy. Thank you for your time and expertise.
> 
> Best regards,  
> Guo Li  
> <image.png>
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