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

Thu Feb 11 21:13:48 EST 2016

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
> >
> > ------------------------------------------------------------------------------
> > Site24x7 APM Insight: Get Deep Visibility into Application Performance
> > APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
> > Monitor end-to-end web transactions and take corrective actions now
> > Troubleshoot faster and improve end-user experience. Signup Now!
> > http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140
> > _______________________________________________
> > mesa-users mailing list
> > mesa-users at lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/mesa-users
> 
> 