[mesa-users] TP-AGB and Post-AGB Mass Loss Issues

Thu Feb 11 21:28:20 EST 2016

Hi Francis,

Thanks once again, I have gone through the 3 instrument papers, but perhaps
I missed something.

I did have problems getting the 4M simulations and above to complete the
TP-AGB phase, but overcame these using efficiency boosted gradT inlist
parameters. I got this clue from reading the instrument papers, however,
the issue there only arose for 15M simulations not 4M and 5M so I was quite
surprised. There does not seem to be a lot of discussion for the kind of
questions I asked for 4M-10M models in the instrument papers.

I will look at the other posts you have mentioned when I get time.

Thanks
ian

On 12 February 2016 at 13:13, Francis Timmes <fxt44 at mac.com> wrote:

> excellent! its generally best to have shown an effort
> at finding the answer to a question that came up a tad short.
> a good example to follow is warrick ball's posts which
> can be found by searching
> https://sourceforge.net/p/mesa/mailman/mesa-users/ .
>
> another source that can answer several of your questions
> are the three mesa instrument papers.
>
> i do not intend to appear as a mean grumpy who is purposely
> not answering your many questions. the goal of my approach
> is analogous to teaching someone how to fish rather than
> simply giving them a fish.
>
> fxt
>
>
>
>
>
> > On Feb 11, 2016, at 6:54 PM, Ian Foley <ifoley2008 at gmail.com> wrote:
> >
> > Hi Francis,
> >
> > Thanks for your answer. Yes, I understood that could be done, but that
> answer could be applied to many of the mesa user questions. Like them (I
> think), I am trying to save a lot of time and of course there is a lot of
> source code and it would take a lot of time to get on top of it. Honestly,
> I was looking for quick answers from those who are far more familiar with
> the code than I am - I only started this serious use of Mesa in November
> last year so there has been a steep learning curve.
> >
> > Indeed, I will look at the code if necessary.
> >
> > Thanks once again
> > Ian
> >
> > On 12 February 2016 at 12:42, Francis Timmes <fxt44 at mac.com> wrote:
> > many of your questions could be answered by
> > you studying the source code. have you looked?
> >
> > fxt
> >
> >
> >
> >
> >
> > > On Feb 11, 2016, at 6:10 PM, Ian Foley <ifoley2008 at gmail.com> wrote:
> > >
> > > As part of my personal education of Stellar Evolution, I have been
> > > running the 1M pre ms to wd test suite case up to 9M and trying out
> > > and learning about the inlist.
> > >
> > > The big issue I see is to understand how mass loss is applied and its
> > > relationship to the thermal pulses.
> > >
> > > Very evident is that if I increase the RGB and AGB scaling factors ( I
> > > have tried from 0.1 up to 8) it flattens out and reduces the number of
> > > thermal pules I suspect this is because as we increase the mass loss
> > > via the mass loss formulae, the larger and more frequent TP's are not
> > > needed to remove the mass.
> > >
> > > This has led me to try to find answers to the following questions.
> > >
> > > 1. Is the mass loss formula applied to every zone to compute the loss?
> > > If yes, why isn't mass loss calculated by using the radial velocity
> > > and computing the amount of matter expelled through the star's outer
> > > zone. If no, how is the formula applied?
> > >
> > > 2. Is the mass loss formula applied only to H? Or is it applied to He
> > > and others as well?
> > >
> > > 3. I have been primarily using the Reimer and Blocker mass loss
> > > formula which is I think a heuristic formula determined by
> > > experimental observations. However, it does seem to be applied fairly
> > > independently of the actual stellar evolution equations. Since we
> > > don't know very well from experiment the number and scale of the TP's
> > > how can we know what is a good scaling factor to use.
> > >
> > > 4. In relation to the new solar wind additions in r8118 over r7624
> > > it's not quite clear to me what is the relation between the Reimer and
> > > Blocker terms and turning on and off the the cool wind dependent on
> > > temperature. Are the Reimer and Blocker factors still needed and the
> > > cool wind temperature terms just configure when they are activated?
> > >
> > > 5. I have similar issues with the convection overshooting. Although it
> > > seems likely to be important it seems we have no idea of the
> > > appropriate number to apply. And, like mass loss, the bigger the
> > > factors you choose the more it dampens the TP's.
> > >
> > > 6. How is the mass loss formula's applied in the post-AGB phase? Does
> > > the Blocker term just switch off at some point and if so when? Why
> > > does it seem that there is no He loss in the post-AGB phase?
> > >
> > > 7. I find it very strange that in the post-AGB phase the lg_LH term in
> > > the terminal output is still up close to the total lg_L even when
> > > there is almost no hydrogen left and what hydrogen there is in the
> > > outer zones of the envelope.
> > >
> > >       step    lg_Tcntr    Teff       lg_LH     lg_Lnuc     Mass
> > > H_rich
> > > H_cntr     N_cntr     Y_surf     X_avg     eta_cntr  zones retry
> > >   lg_dt_yr    lg_Dcntr    lg_R       lg_L3a    lg_Lneu     lg_Mdot
> > > He_core    He_cntr    O_cntr     Z_surf     Y_avg     gam_cntr  iters
> > > bckup
> > >     age_yr    lg_Pcntr    lg_L       lg_LZ     lg_Psurf    lg_Dsurf
> > > C_core
> > > C_cntr     Ne_cntr    Z_cntr     Z_avg     v_div_cs     dt_limit
> > >
> > >      39400   8.211499  2.889E+04   4.255626   4.354482   0.985786
> > > 0.000116   0.000000   0.000000   0.374091   0.000065  49.353686   2183
> > >  5037
> > >  -5.801543   7.277248   0.753659   3.545685   3.889458  -4.012795
> > > 0.985670   0.000000   0.579524   0.020125   0.001666   7.754729      6
> > >    31
> > > 3.5571E+07  24.321104   4.303656   3.038122   3.281056 -10.342147
> > > 0.982096   0.394597   0.001949  1.000E+00  9.983E-01  0.000E+00
> > > varcontrol
> > >
> > > Is this OK or is there a problem with the software?
> > >
> > >
> > > I would be very grateful for any help in answer to these questions
> > > Ian
> > >
> > >
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