[Mesa-users] celebrating a mesa milestone -- version 10000

Josiah Schwab jwschwab at ucsc.edu
Tue Sep 12 13:31:27 EDT 2017


Hi All,

> a release message will follow with details.

Here is a list of notable changes in this release.


Added the weak reaction rates from Suzuki, Toki, and Nomoto (2016)
[http://adsabs.harvard.edu/abs/2016ApJ...817..163S]. These rates are
relevant for high density O-Ne-Mg cores.  We thank Prof. Toshio Suzuki
for providing these tables and giving permission for their inclusion in
MESA.

These tables are off by default.  They can be activated by setting
    use_suzuki_weak_rates = .true.
in your star_job namelist.


Simplified the hot/cool wind scheme so that now there are only two controls.
T > Hot_wind_full_on_T : use the hot wind scheme
T < Cool_wind_full_on_T : Use the cool wind scheme
Ramp between hot and cool winds for intermediate T.


New diffusion coefficients added from Stanton & Murillo (2016)
[http://adsabs.harvard.edu/abs/2016PhRvE..93d3203S]. These are now the
default coefficients. The old default coefficients can be accessed with
the inlist controls option diffusion_use_paquette = .true.


Controls were added to enable moving the range over which
crystallization occurs. Previously this was hard-coded to occur smoothly
over the range Gamma=150-175, but these parameters are now adjustable in
star_job via the options PC_Gamma_start_crystal and
PC_Gamma_full_crystal.


Added threshold_for_smooth_gradL_composition_term parameter, which
influences how the composition term in the Ledoux temperature gradient
gradL is smoothed. Previously, the smoothing was applied to *all* cells,
using a discrete Gaussian filter with a width given by
num_cells_for_smooth_gradL_composition_term. However, this
indiscriminate smoothing tends to broaden the gradL composition term,
making it 'bleed' into regions where there is no composition
gradient. The new threshold_for_smooth_gradL_composition_term parameter
allows the user to specify a threshold, such that the smoothing is now
applied only to *contiguous* regions which exceed the threshold. By
setting the threshold to some small but non-zero value, most of the
spurious broadening can be avoided.

Also added a corresponding threshold_for_smooth_brunt_B parameter, which
works in the same way except that smoothing of brunt_B (the composition
term in the Brunt-Vaisala frequency) is controlled.



Some capabilities that will be described in the upcoming MESA Instrument
paper IV (e.g., STELLA) are included in MESA in a preliminary form but
are not yet ready for general use.  Please wait for the next release (in
approximately 4-6 weeks) to begin using them.


Best,
Josiah


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