[Mesa-users] Blue loops

[Jeremy Sakstein]

One final question: I can’t  seem to get blue loops that cross the
instability strip for say 13M models.

Do I need to change the controls in the inlist due to other physical
processes kicking in?

Cheers,

Jeremy

On Wed, Apr 3, 2019 at 12:54 PM Jeremy Sakstein <sakstein at sas.upenn.edu>
wrote:

> Thanks Radek,
>
> It looks very similar to the inlist I am using so that is good. The only
> difference is the mixing length scheme. I think for my purposes as long as
> I am consistent this should not matter too much.
>
> Cheers,
>
> Jeremy
>
> On Wed, Apr 3, 2019 at 11:34 AM Radek Smolec <smolec at camk.edu.pl> wrote:
>
>> Jeremy,
>> for 5M_cepheid_blue_loop see the recent public release.
>> I attach the relevant inlist for your reference.
>>
>> You may also take a look at Section 2.4.2 of the instrument paper:
>> https://arxiv.org/abs/1903.01426
>> Tracks in Figure 13 were computed using this test_suite example.
>> Cheers,
>> Radek
>>
>>
>> śr., 3 kwi 2019 o 17:25 Jeremy Sakstein <sakstein at sas.upenn.edu>
>> napisał(a):
>>
>>> Thanks Radek,
>>>
>>> Comments below.
>>>
>>> Cheers,
>>>
>>> Jeremy
>>>
>>> On Wed, Apr 3, 2019 at 11:21 AM Radek Smolec <smolec at camk.edu.pl> wrote:
>>>
>>>> Dear Jeremy,
>>>>
>>>> śr., 3 kwi 2019 o 16:55 Jeremy Sakstein <sakstein at sas.upenn.edu>
>>>> napisał(a):
>>>>
>>>>> Dear Mesa community,
>>>>>
>>>>> I've been using MESA to calculate blue loops for Z=0.0006 Cepheids in
>>>>> the mass range [image: 5-13 M_\odot] and had a couple of questions I
>>>>> was hoping you could answer.
>>>>>
>>>>> Nominally, I am a theorist so my approach so far has been to use the
>>>>> inlist for 7M pre MS to AGB with
>>>>>
>>>> You may also start with 5M_cepheid_blue_loop in the test_suite.
>>>>
>>>
>>> Thanks. I didn't see this in the test suit (I am using 10398*)*
>>>
>>>
>>>>
>>>>
>>>>>
>>>>> mixing_length_alpha = 1.73
>>>>> initial_z = 0.0006
>>>>> alpha_semiconvection = 0.1
>>>>> use_Ledoux_criterion = .true.
>>>>>
>>>>> and cary the initial mass over this range.
>>>>>
>>>>> Initially, I was only using 7-9 [image: M_\odot] but now I need to
>>>>> push to a larger range and am getting funny results e.g. the loops cross.
>>>>>
>>>> What do you mean by "the loops cross"? That single evolutionary track
>>>> passes through the same (Teff, L) point? For larger masses this is
>>>> expected.
>>>>
>>>
>>> Yes, that is what I mean. Good to know this is normal.
>>>
>>>
>>>>
>>>>
>>>>>
>>>>> I am wondering if what I am doing is sensible given that the physics
>>>>> of these objects could be very different depending on mass. In particular,
>>>>> I am not sure what people typically use for e.g. the semi-convection
>>>>> parameter at higher and lower masses.
>>>>>
>>>> I'm not sure what is the range of semi-convection parameter considered
>>>> in the literature. 0.1 seems raesonable.
>>>> Note that the shape and extent of the loops is very sensitive to many
>>>> parameters: chemical composition, overshooting from the convective regions,
>>>> rotation...
>>>> Cheers,
>>>> Radek
>>>>
>>>>
>>>>> I'd be grateful for any help you can give.
>>>>>
>>>>> Cheers,
>>>>>
>>>>> Jeremy
>>>>> _______________________________________________
>>>>> mesa-users at lists.mesastar.org
>>>>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>>>>
>>>>>
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