[Mesa-users] Convergence problems for low mass planets

[Isaac Malsky]

Hi Dr. Schwab and Dr. Farmer (and all),

Thanks so much for the help! I appreciate the analysis of the EOS issues.

Best,
Isaac

On Wed, May 1, 2019 at 10:40 PM Josiah Schwab <jwschwab at ucsc.edu> wrote:

> Hi Isaac,
>
> Thanks.  This indeed looks like EOS issues.  The default logQ limit is 5.0
> in MESA, but you can run into trouble before that.  The timestep falls
> because any iteration that evolves for long enough to reach a place where
> there's an EOS problem fails.  So there's sort of a "wall".
>
> If you set report_ierr = .true. you can see the details of the failing
> calls. You'll find gamma1 is going negative around logRho = 0, logT = 3.5.
>
> If you look in the SCVH paper (
> https://ui.adsabs.harvard.edu/abs/1995ApJS...99..713S/abstract) you'll
> see this is right around the "notch" in their coverage and the PPT.
>
> I've attached a plot showing gamma1 & your profiles.  Once the model
> touches that dark blue area it's dead.  (This also shows you probably
> shouldn't feel great about the irradiated model that is just barely running
> to completion.)
>
> There's no short-term fix.  We're aware of
> https://ui.adsabs.harvard.edu/abs/2019ApJ...872...51C/abstract and are
> working towards incorporating it in MESA on the timescale of next
> instrument paper.
>
> Josiah
>
>      hydro_call_number, s% dt, dt, dt/secyer, log dt/yr          98
> 1.1438023329131436D+16    1.1438023329131436D+16    3.6244277104109460D+08
>   8.5592394421258557D+00
>
>                                                  csound         410
> 0.0000000000000000D+00
>                                            s% gamma1(k)         410
>  -1.9546796997627285D-02
>                                                s% cp(k)         410
> 1.6336434229865569D+08
>                                                 s% P(k)         410
> 9.9568253369982886D+11
>                                              s% Pgas(k)         410
> 9.9568253369953088D+11
>                                               s% rho(k)         410
> 7.0483665705460108D-01
>                                                 s% T(k)         410
> 3.2968963255952235D+03
>                                                  logRho         410
>  -1.5191151727684368D-01
>                                                    logT         410
> 3.5181052905068673D+00
>                                                    abar         410
> 1.2479768720681050D+00
>                                                    zbar         410
> 1.0857440384523727D+00
>  do_eos_for_cell k         410
>  s% lnPgas_flag T
>                                                    z =
>  1.9999999999999463D-02
>                                                    x =
>  7.4000000000000055D-01
>                                                  Xhe3 =
> 1.9999183706787520D-05
>                                                  Xhe4 =
> 2.3998000081629320D-01
>                                               sum(xa) =
> 1.0000000000000000D+00
>                                                 abar =
>  1.2479768720681050D+00
>                                                 zbar =
>  1.0857440384523727D+00
>                                                 Pgas =
>  9.9568253369953088D+11
>                                              logPgas =
>  1.1998120888784946D+01
>                                                  rho =
>  7.0483665705460108D-01
>                                               logRho =
> -1.5191151727684368D-01
>                                                    T =
>  3.2968963255952235D+03
>                                                 logT =
>  3.5181052905068673D+00
>                                                 logQ =
>  4.8118779017094218D+00
>                                                 logW =
> -2.0743002732425229D+00
>
>
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