[Mesa-users] Blue loops

[Radek Smolec]

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.


>
> 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.


>
> 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
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20190403/5c0e420e/attachment.html>