# [Mesa-users] Blue loops

Wed Apr 3 11:33:44 EDT 2019

```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,

śr., 3 kwi 2019 o 17:25 Jeremy Sakstein <sakstein at sas.upenn.edu> napisał(a):

>
>
> 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
>>>
>>
>
> 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,
>>
>>
>>>
>>> Cheers,
>>>
>>> Jeremy
>>> _______________________________________________
>>> mesa-users at lists.mesastar.org
>>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>>
>>>
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