[mesa-users] Cepheid loops - comparison

[Radek Smolec]

Dear MESA users,

Since the issues of comparison between other codes and MESA, and the
sensitivity of the blue loops were raised recently in this forum I want to
share some results.
 In the attached pdf you can find the evolutionary tracks for intermediate
mass stars and different metallicities computed with MESA and compared with
the published tracks (Bertelli et al. 2009, Padova code). In the inlist the
parameters were set to match the ones used by Bertelli et al (MLT alpha,
overshooting, etc.) closely. The tracks are in a very good agreement for
all metallicities. I am a little concerned with the location of RGB. The
MESA tracks are shifted to the red; smaller the metallicity larger the
shift. The location of RGB depends primarily on the mixing length - I used
alpha=1.68, as adopted in the Padova code. Now I am also checking different
MLT options in MESA but so far it doesn't help. Any other ideas how to
shift the RGB (without changing alpha)?

I have done similar comparison also for the BaSTI tracks (again adjusting
MESA parameters to match that used by Pietrinferni et al. closely) and got
similar agreement between MESA and BaSTI tracks.

All computations were done with MESA 4631/SDK running on Ubuntu. Exemplary
inlist is attached - M, Z and name of the ZAMS model's file (which I
created) were changed for particular tracks.
Note that if this inlist is run with the current version of MESA the error
will be reported as the control "use_lnE_for_eps_grav = .true." is no
longer available. Is .true. the default value now?

Now I investigate the effects of rotation on the loops and have some
problems with it, which I will address in a separate message.
cheers,
Radek
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