[mesa-users] ERROR: donor accreting, terminating evolution

[jiakun1219]

Thanks very much Pablo, my version is 7499, and I woud update it as you suggested.




At 2015-07-28 21:07:25, "Pablo Marchant" <pamarca at gmail.com> wrote:

Sorry, had written this reply but forgot to sent it:


Please keep mesa-users in the loop while replying.


This is an old bug that was fixed some versions ago, that bit of code you mention should not be called with the roche_lobe or Ritter scheme, and in old versions it could produce this bug somewhat at random. Which MESA version are you using? I'd suggest you try r7624


The purpose of the fixed_delta_mdot IS to produce a change in sign in the mass transfer rate, which means that the donor star switches during mass transfer. This is used by the experimental "contact" scheme. Using the other mass transfer schemes such a switch should not happen, which is why the ERROR message appears and evolution is terminated.


On Tue, Jul 28, 2015 at 2:58 PM, jiakun1219 <jiakun1219 at 163.com> wrote:


Dear Pablo,
I have just find the error comes from the b% fixed_delta_mdot.
When the value of b% fixed_delta_mdot bigger than the difference of new_mdot and explicit_mdot without the b% implicit_scheme_tolerance,
the code would take another step_loop and adding b% fixed_delta_mdot to new_mdot which would have a positive value and run over,
so it is just a numberical error here about donor accreating.
Then I limit the value of b% fixed_delta_mdot in binary_mdot, that would be OK, so would it be a bug in the code?
And the attachment is my modified binary_mdot.f90.
         if (abs(b% fixed_delta_mdot) .gt. abs(abs(b% mtransfer_rate) - abs(explicit_mdot))) then
            b% fixed_delta_mdot = 0.1 * b% implicit_scheme_tolerance * &
            b% fixed_delta_mdot/(abs(b% fixed_delta_mdot)/abs(explicit_mdot))
         end if
Thanks very much!
Kun Jia


Dear Pablo,
I'm very sorry for missing the attachments..
And I just find the error comes from the mdot_next = b% mdot_hi + b% fixed_delta_mdot (in binary_mdot.f90).
After some iteration adding of b% fixed_delta_mdot,  the mdot_next could be positive while the new_function_to_solve still >= 0, so it makes the error donor accreating.
Also I have changed the value of fr and fr_limit in the inlist, but it seems do not work, and when I use the mdot_scheme = "roche_lobe" rather than "Ritter", it' would be OK. So if I want to choose the "Ritter" mode here, what can I do? Thanks very much!
Kun Jia







在 2015-07-27 18:09:04，"Pablo Marchant" <pamarca at gmail.com> 写道：

Attachments are missing.


On Sun, Jul 26, 2015 at 4:12 PM, jiakun1219 <jiakun1219 at 163.com> wrote:

Dear all,

When I evolve a binary system it makes a error as : donor accreting, terminating evolution.
And I have checked the problems lie on the positive value of b% s_donor% mstar_dot,
so I wonder why a Roche lobe overflowing donor star could have a positive mdot ?
Where I use the test_suite as binary_donor_only_implicit_mdot, and the inlists and .src files are attached.
Thanks very much!

Sincerely,
Jia Kun









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--

Pablo Marchant Campos
M.Sc on Astrophysics, Universidad Católica de Chile
PhD student, Argelander-Institut für Astronomie











--

Pablo Marchant Campos
M.Sc on Astrophysics, Universidad Católica de Chile
PhD student, Argelander-Institut für Astronomie
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