[mesa-users] Some questions on Astero and convection

[João Faria]

Hi all,

I have been using MESA to do asteroseismology for a while (learned a lot 
from Instrument Paper 2!) but still have some questions about the astero 
module.

    - In the *example_astero* test, the option of adding an atmosphere
    to adipls is turned off. I understand that only specific cases would
    require such an atmosphere going to small optical depths (like WDs
    probably?) and that including or not the atmosphere will probably
    only cause a systematic "surface effect". Is it reasonable to do
    main-sequence and sub-giant fitting without including the atmosphere?

    - in a related question, the add_atmosphere = .true. option adds a
    'Paczynski_grey' atmosphere to the model. Can we use it with either
    which_atm_option = 'photosphere_tables' or which_atm_option
    ='Krishna_Swamy' ?

    - yet another related question: is it ok to create a pre-ms model with
    which_atm_option ='Krishna_Swamy' if we have it relaxed for 200
    steps (pre_ms_relax_num_steps = 200)?

    - MESA gives the possibility of calculating delta_nu from a linear
    fit to the radial modes. This will also calculate delta_nu_sigma as
    the error in the fit, but this error will usually be one or two
    orders of magnitude smaller than the "real" error in delta_nu. Is it
    possible to add an option to use delta_nu_sigma from the inlist even
    if doing the fit? Something like setting delta_nu = -1 but still
    using, for example, delta_nu_sigma = 5.0 if set in the inlist.

Still on the astero module, I found a very tiny bug in the echelle plot 
routine. In line 258 of the file *pgstar_echelle_plot.f* it should say
     if (have_nonradial) call show_model(l3_freq_corr(i))
instead of
     if (have_nonradial) call show_model(l2_freq_corr(i))
otherwise the l=3 modes appear "connected" to the l=2 ones.


About the convection I just have a question/wish. Will MESA in the near 
future be able to calculate convection according to the treatment of 
Canuto & Mazzitelli? Can we expect much difficulty in implementing 
something like what CESAM does in other_mlt?


Sorry, this turned out a little lengthy.
Thank you in advance

Jo\E3o Faria
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