[mesa-users] 1M_pre_ms_to_wd

Mon Oct 19 13:53:25 EDT 2015

maybe you’ve discovered a new low-metalliity transient mechanism!

fxt

> On Oct 19, 2015, at 9:49 AM, Bill Paxton <paxton at kitp.ucsb.edu> wrote:
> 
> Hi Willie,
> 
> Thanks for running that.  I decided to do the next step -- run the 1M_pre_ms_to_wd test case but with Z reduced to 1d-3.  It runs smoothly and quickly to a cooling WD, but then it explodes!  By "it" I don't mean mesa; I mean there is an explosion of the small remaining He envelope.
> 
> It gets to this point without problems (at model 2700) -- one might reasonably declare victory and stop now, but I didn't.
> <H_R.pdf>
> But if you look at the profile of model 2700, you find this going on inside:
> <plot_T_RHO.pdf>
> <logT.pdf>
> 
> 
> <Power.pdf>
> <Abundances.pdf>
> A huge and very late helium flash. The luminosity jumps back up to tip of AGB levels. But the code cannot cope with the strength of the mass ejection event, so it terminates. 
> 
> Here's the final HR showing the return to the AGB.
> <H_R.pdf>
> 
> Cheers,
> Bill
> 
> 
> 
> 
> 
> 
> On Oct 19, 2015, at 2:26 AM, Willie Strickland wrote:
> 
>> I have run the test case to which Bill refers (1M_pre_ms_to_wd) many times to various stopping points including all the way to WD.  
>> 
>> I primarily use this test and the work directory (15M star on which you built your inlist) anytime I install a new version of MacOS or of MESA.  I compare the results to previous runs to make sure the final profile and final model are in agreement and I also pay attention to the time taken to run.
>> 
>> I cannot attest to the astrophysical accuracy of my results, but would be happy to share specifics with the mailing list for evaluation if that would be helpful.
>> 
>> After installing El Capitan, I started with a pre-main sequence model and ran to WD in 58 minutes and 29 seconds on my 4 year old, 2 core i7 MacBook Pro specifying 4 threads.  Attached is the Grid8 plot from the final model.
>> 
>> My inlist does have some modifications which I have found helpful in running my tests, but may not be as accurate.
>> 
>> Willie
>> 
>> 
>> <grid8_000170.png>
>> 
>> 
>>> On Oct 18, 2015, at 3:15 PM, Bill Paxton <paxton at kitp.ucsb.edu> wrote:
>>> 
>>> Hi Noah,
>>> 
>>> There is a test case that runs Z=0.02, 1Msun from pre-main-sequence to cool white dwarf.  You should run that test to get an idea of where the runtime is spent --- e.g., climbing the RGB.  Then let us know what you find.  Perhaps you'll find ways to save models along the way so that students can use them to run different interesting parts of the evolution (e.g., he core flash) without the computational cost of running the entire evolution.  I think that's probably a better approach than trying to make a "brain dead" version of mesa that gives up lots of accuracy in an attempt to run fast.  (for the fast but loose approach, you might want to run my old "EZ" code -- but I don't recommend it.)
>>> 
>>> bill
>>> 
>>> btw: it is okay to say "thank you" when I volunteer to look at something for you. ;D
>>> 
>>> 
>>> 
>>> 
>>> On Oct 18, 2015, at 1:00 PM, Glasman, Noah B wrote:
>>> 
>>>> Here is my inlist_project for that run. I am just trying to run the entire life of a 1Msun star with Z = 0.001. Does anyone know if MESA works on OSX El Capitan yet?
>>>> 
>>>> ! inlist to evolve a 15 solar mass star
>>>> 
>>>> ! For the sake of future readers of this file (yourself included),
>>>> ! ONLY include the controls you are actually using.  DO NOT include
>>>> ! all of the other controls that simply have their default values.
>>>> 
>>>> &star_job
>>>> 
>>>>   ! begin with a pre-main sequence model
>>>>     create_pre_main_sequence_model = .true. 
>>>> 
>>>>   ! save a model at the end of the run
>>>>     save_model_when_terminate = .false.
>>>>     save_model_filename = '15M_at_TAMS.mod'
>>>> 
>>>>   ! display on-screen plots
>>>>     pgstar_flag = .true.
>>>> 
>>>> / !end of star_job namelist
>>>> 
>>>> 
>>>> &controls
>>>> 
>>>>   ! starting specifications
>>>>     initial_mass = 1 ! in Msun units
>>>>     initial_Z = 0.001
>>>>     !max_model_number = -1
>>>> 
>>>>   ! stop when the star nears ZAMS (Lnuc/L > 0.99)
>>>>     !Lnuc_div_L_zams_limit = 0.99d0
>>>>     !stop_near_zams = .false.
>>>> 
>>>>   ! stop when the center mass fraction of h1 drops below this limit
>>>>     !xa_central_lower_limit_species(1) = 'h1'
>>>>     !xa_central_lower_limit(1) = 1d-3
>>>> 
>>>> / ! end of controls namelist
>>>> 
>>>> 
>>>> 
>>>> 
>>>> From: Bill Paxton <paxton at kitp.ucsb.edu>
>>>> Sent: Sunday, October 18, 2015 12:23 PM
>>>> To: mesa-users at lists.sourceforge.net group group
>>>> Subject: [mesa-users] MESA in education -- where's the website for this?
>>>>  
>>>> Dear MESA-USERS who use mesa for teaching,
>>>> 
>>>> How do you manage with the issues Noah raises in the attached email?  
>>>> 
>>>> Have you found problems that are good for combining academic interest and short runtimes?
>>>> 
>>>> Wouldn't it be great if there were a website/forum/social-media-something-or-other specifically to serve "mesa in education"?
>>>> 
>>>> -Bill
>>>> 
>>>> 
>>>> 
>>>> 
>>>> On Oct 17, 2015, at 6:05 PM, Glasman, Noah B wrote:
>>>> 
>>>>> I am wondering if there is a way to speed up how fast MESA runs on my computer? At the moment it takes an hour plus to run it for a 1Msun star with Z = 0.001 and after an hour it's only at 6.349e9 years. Is there something I can do to speed up the program or maybe allocate how much ram it uses? At the pace it is going it is almost impractical to use for any research or classwork for my Astronomy class. I have a 2012 Macbook Pro 13 inch, 4gb DDR3 RAM, 2.5 GHz Intel Core i5 cpu, with OSX 10.10.5. I am running MESA-r7624, with  Version 20150908 of the MESA-sdk.
>>>>> 
>>>>> 
>>>>> Sincerely,
>>>>> Noah Glasman 
>>>>> ------------------------------------------------------------------------------
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>>>>> mesa-users at lists.sourceforge.net
>>>>> https://lists.sourceforge.net/lists/listinfo/mesa-users
>>>> 
>>>> 
>>> 
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