[Mesa-users] Blue loops

Radek Smolec smolec at camk.edu.pl
Wed Apr 3 11:21:32 EDT 2019

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

> 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,

> 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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