# MESA

## Latest News

This web documentation corresponds to the most recent MESA release (r10108). Documentation for past versions can be found here.

If you find errors or formatting issues, please email Josiah Schwab using this link.

### chem_isotopes_filename ¶

this file is in chem_data in mesa_data_dir

### pause_before_terminate ¶

if true, then will pause before terminate run. this can be useful if you’d like a chance to look at the final model pgstar windows before they go away.

## cache directories ¶

### rates_cache_dir ¶

mesa uses caches to improve performance. the default location for these is in the mesa/data directory, but in some situations it is useful to keep the caches separately so, for example, multiple users can share the code and each can have a separate set of caches. ‘’ means use default location for cache.

The need for separate caches arises in cases where we need to put the main mesa directory in a location that is “read only” for a group of users (such as in a system directory that requires “root” or “superuser” to write). In that case the caches must be moved out of the main directory to locations that the user can write.

if you specify cache directories, use a separate one for each. e.g., something like this

eosDT_cache_dir = '/Users/bpaxton/mesa_caches/eosDT_cache'
eosPT_cache_dir = '/Users/bpaxton/mesa_caches/eosPT_cache'
eosDE_cache_dir = '/Users/bpaxton/mesa_caches/eosDE_cache'
ionization_cache_dir = '/Users/bpaxton/mesa_caches/ionization_cache'
kap_cache_dir = '/Users/bpaxton/mesa_caches/kap_cache'
rates_cache_dir = '/Users/bpaxton/mesa_caches/rates_cache'


If you give an empty string for the cache_dir, then if you have set the environment variable MESA_CACHES_DIR, then the cache is a subdirectory of that with one of the following names: eosDT_cache, eosPT_cache, kap_cache, ionization_cache, rates_cache if MESA_CACHES_DIR is not set or is the empty string, then the cache is a subdirectory of the corresponding data subdirectory, such as data/rates_data/cache for the rates cache.

# output ¶

### save_star_job_namelist ¶

dumps all values for &star_job controls to file

### star_job_namelist_name ¶

if empty, uses a default name

### show_log_description_at_start ¶

set this false if you want to skip the initial terminal output

### show_net_species_info ¶

if true, then output a list of the species in the current net

### show_net_reactions_info ¶

if true, then output information about the reactions in the current net

### list_net_reactions ¶

if true, then output a simple list of the reactions in the current net

### show_eqns_and_vars_names ¶

if true, then output a list of the names of the equations and variables

### pgstar_flag ¶

if true, activates pgplot output

### disable_pgstar_for_relax ¶

if true, turn off pgstar during relax operations

### save_pgstar_files_when_terminate ¶

if true, then when the run terminates, pgstar outputs files for plots that have file_flag = .true. independently of the corresponding file_interval.

### history_columns_file ¶

if null string, use default.

### profile_columns_file ¶

if null string, use default.

### save_model_number ¶

at any point during the run, you can save a model for later use

### save_model_when_terminate ¶

save final model when a run terminates

### save_model_filename ¶

saved model root filename

### save_photo_when_terminate ¶

if true, then save photo for last model before terminate the run

### profile_model_number ¶

write profile for a specific model number

### filename_for_profile_when_terminate ¶

write profile to a given name upon termination

### save_pulse_data_filename ¶

write pulsation info for the model (format given by s% pulse_info_format)

### stella_v_wind ¶

write stella info for the model

the mesa/star routine for creating stella files knows about the following species: h1, he3, he4, c12, n14, o16, ne20, na23, mg24, al27, si28, s32, ar36, ca40, ti44, cr48, cr60, fe52, fe54, fe56, co56, ni56 if your net includes other species, they will be ignored when creating the stella file. on the other hand, any species missing from this list will simply be given 0 abundance. see mesa/stella/README for details.

### internals_num ¶

write internals – for debugging only write if >= 0

### report_backups ¶

in case you want some extra info about retries or backups

# starting model ¶

By default at the start of a run a zams starting model is loaded, and then the initial_mass, initial_z, and initial_y are adjusted as necessary. However, there are alternatives. you can use a model you saved previously, or you can request the system to create a pre-main-sequence model.

BTW: the system finds the zams file by using the control called zams_filename the default zams file is for Z=0.02 and lives in data/star_data/zams_models. You can create your own zams file and use it instead – see test_suite/create_zams.

### saved_model_name ¶

If load_saved_model is true, then use the specified initial model.

### create_pre_main_sequence_model ¶

If true, the code will create a starting model with uniform composition, a core temperature below 10^6 so no nuclear burning, and uniform contraction for enough luminosity to make it fully convective.

The mass is initial_mass from the controls namelist.

if initial_y is < 0 in the controls, then code uses 0.24 + 2*initial_z for initial_y.

The h1 mass fraction is set to 1 - (initial_y + initial_z). The he3 and he4 mass fractions are set according to initial_y with relative amounts set according to the AG89 solar mass fractions (from chem_def).

The metallicity is initial_z from the controls namelist with the metals fractions set according to the GS98 values (from chem_def).

to set the metals fractions, use initial_zfracs (described below)

### saved_model_for_merger_2 ¶

If create_merger_model is true, then create a star by merging the two models provided.

### pre_ms_T_c ¶

Initial center temperature (must be below 1d6). If you have initial convergence problems creating a pre-ms model, you might try different values for pre_ms_T_c – that sometimes helps.

### pre_ms_guess_rho_c ¶

Guess for initial center density; set to 0 to let the code pick.

### pre_ms_d_log10_P ¶

Suggested spacing in pressure between points; set to 0 to let the code pick.

### pre_ms_logP_surf_limit ¶

Model contruction is from inside out and stops when reaches either of the following limits.

### pre_ms_relax_num_steps ¶

Let pre-ms model settle in for this many steps before changing anything else.

### create_initial_model ¶

This is an alternative to create_pre_main_sequence_model. If true, creates an adiabatic, contracting model for given mass and radius. Assumes no nuclear burning and constant entropy. Ignores radiation pressure. Uses star controls initial_y and initial_z to set X, Y, and Z. Uses initial_zfracs to set abundances of metals.

Note: if you’d like to do-it-yourself, then you can use other_build_initial_model. In that case, in addition to setting create_initial_model, also set star controls use_other_build_initial_model. Then your run_star_extras routine will be called instead of the standard one.

### mass_in_gm_for_create_initial_model ¶

Radius in cm and mass in grams.

### initial_model_relax_num_steps ¶

Let initial model settle in for this many steps before changing anything else.

### initial_model_eps ¶

Integration accuracy.

# when to stop ¶

### steps_to_take_before_terminate ¶

If > 0, stop after taking this many steps. Sets max_model_number = model_number + steps_to_take_before_terminate. Ignore if <= 0.

### stop_if_this_file_exists ¶

At each step, the code will try to open this file. If the file exists, it will terminate the run. If the file doesn’t exist, it will keep going.

# modifications to model ¶

These controls enable one to alter the MESA model at the start of a run (./rn) or after a restart (./re). Controls that only apply to the first model have ‘initial’ in their names, and are ignored for restarts.

### initial_age ¶

if true, set initial age in years

### initial_model_number ¶

if true, set initial model number

### seconds_for_initial_dt ¶

if true, set initial timestep, dt, in years

### limit_initial_dt ¶

Like set_initial_dt, but does not increase current value for dt_next. Used in conjunction with years_for_initial_dt and seconds_for_initial_dt.

dt_next = min(dt_next, years_for_initial_dt*secyer)


### set_uniform_initial_composition ¶

Set uniform composition. This is useful with create_pre_main_sequence_model.

### initial_he4 ¶

if set_uniform_initial_composition is true, then set hydrogen and helium mass fractions according to the following: If no h2 in current net, then this will be added to h1. If no he3 in current net, then this will be added to he4.

### initial_zfracs ¶

if set_uniform_initial_composition is true, then set metal fractions z fractions – select one of the options defined in chem/public/chem_def :

• AG89_zfracs = 1
• GN93_zfracs = 2
• GS98_zfracs = 3
• L03_zfracs = 4
• AGS05_zfracs = 5
• AGSS09_zfracs = 6
• L09_zfracs = 7
• A09_Prz_zfracs = 8

for example, initial_zfracs = 3 for GS98_zfracs or set initial_zfracs = 0 to use the special list of z fractions specified in controls (i.e., z_fraction_li, z_fraction_be, z_fraction_b, etc.)

### dump_missing_metals_into_heaviest ¶

this controls the treatment metals that are not included in the current net. if this flag is true, then the mass fractions of missing metals are added to the mass fraction of the most massive metal included in the net. if this flag is false, then the mass fractions of the metals in the net are renormalized to make up for the total mass fraction of missing metals.

### set_uniform_xa_from_file ¶

an alternative to the above set_uniform_initial_composition method. if set_uniform_initial_xa_from_file is .true., read list of iso name and mass fraction pairs from file file_for_uniform_xa and use them to set uniform composition. E.g., to convert the star to pure fe56, a file with just the following line will work.

fe56   1.0


### mix_section_nzhi ¶

fully mix section of model

### mix_initial_envelope_down_to_T ¶

fully mix envelope from surface down to given temperature

### set_abundance_nzhi ¶

given a chem_name from chem_def, set its abundance to be new_frac in a given range of cells, from set_abundance_nzlo to set_abundance_nzhi

### replace_element_nzhi ¶

replace one iso by another in a given range of cells chem_name1 and chem_name2 from chem_def

### relax_composition_filename ¶

relax composition from current to specified over number of steps. relax_composition_filename holds the desired composition profile information file format for relax composition

1st line: num_points num_species
then 1 line for for each point where define desired composition
xq xa(1) ... xa(num_species)
xq = fraction of xmstar exterior to the point
where xmstar = mstar - M_center
the interpolation routines require that the xq values which
appear in your file must be monotonically increasing
xa(i) = mass fraction of i'th species


NOTE: it is up to you to ensure that the current net isotopes match the species in the composition file. You can set show_net_species_info = .true. to check the isotopes in the net.

### relax_initial_to_xaccrete ¶

Like relax_initial_composition (and uses num_steps_to_relax_composition), but new composition is set by current specification of accretion abundances.

some modifications must be done gradually over several steps in “pseudo” evolution these operations have “relax” in their names. many have an alternative, with “set” in name, that simply make the change all at once. the “set” version is fine if star can manage to converge the modified model. but for larger changes where that’s not possible, you’ll need to “relax” instead.

### new_Y ¶

relax_Y = .true. gradually changes average Y, reconverging at each step. change_Y = .true. changes abundances; doesn’t reconverge the model. note: relax_dY in the controls inlist determines the rate of change

### new_Z ¶

relax_Z = .true. gradually changes average Z, reconverging at each step. change_Z = .true. simply changes abundances; doesn’t reconverge the model. note: relax_dlnZ in the controls inlist determines the rate of change

### lg_max_abs_mdot ¶

Gradually change total mass by a wind to new_mass. lg_max_abs_mdot = -4 means max abs mdot 1d-4 msun/year; Set <= -100 to let code pick.

### change_mass_years_for_dt ¶

Gradually rescale mass of star to new_mass. Rescales star mass without changing composition as function of m/mstar.

### relax_angular_momentum_filename ¶

relax angular momentum from current to specified over a certain amount of relaxation timescales. This is done by adding an extra torque term of the form

s% extra_jdot(k) =  &
(1d0 - exp_cr(-s% dt/(s% job% timescale_for_relax_angular_momentum*secyer))) * &
(desired_angular_momentum(k) - s% j_rot(k))/s% dt


and evolving the star without changing the composition for num_timescales_for_relax_angular_momentum times timescale_for_relax_angular_momentum. To circumvent convection we limit the acceleration of convective velocities using min_T_for_acceleration_limited_conv_velocity = 0 (see controls.defaults), and the timescale for relaxation should be very short (less than a second).

relax_angular_momentum_filename holds the desired angular momentum profile information file format for relax angular momentum

1st line: num_points
then 1 line for for each point where define desired angular momentum
xq angular_momentum
xq = fraction of xmstar exterior to the point
where xmstar = mstar - M_center
angular_momentum = specific angular momentum in units of cm^2/s


### get_entropy_for_relax_from_eos ¶

relax entropy from current to specified over a certain amount of relaxation timescales. This is done by adding an extra heating term of the form

s% extra_heat(k) =  &
(1d0 - exp_cr(s%lnS(k))/desired_entropy(k))*exp_cr(s%lnE(k))/(timescale_for_relax_entropy*secyer)


and evolving the star without changing the composition for num_timescales_for_relax_entropy times timescale_for_relax_entropy. To circumvent convection we limit the acceleration of convective velocities using min_T_for_acceleration_limited_conv_velocity = 0 (see controls.defaults), and the timescale for relaxation should be very short (less than a second).

relax_entropy_filename holds the desired entropy profile information file format for relax entropy

1st line: num_points
then 1 line for for each point where define desired entropy
xq entropy
xq = fraction of xmstar exterior to the point
where xmstar = mstar - M_center
entropy = specific entropy in units of erg/gr/K


the interpolation routines require that the xq values which appear in your file must be monotonically increasing.

In case the entropy is not readily available, pairs of values of two other thermodynamic variables can be provided. The entropy is then computed using the eos module, and the composition of the stellar model (which can be set using relax_initial_composition). This is set by the option get_entropy_for_relax_from_eos which can take the values

• ’’: if empty, then input file directly specifies the entropy
• ‘eosDT’: input file includes density and temperature
• ‘eosPT’: input file includes gas pressure and temperature
• ‘eosDE’: input file includes density and specific internal energy

when any of the eos* options is used, then each line in the input file must contain three columns instead of two, specifying the values of the two thermodinamic variables used in the order specified above. So, for example, when using ‘eosDT’ the format of the input file is

1st line: num_points
then 1 line for for each point where define desired entropy
xq density temperature
xq = fraction of xmstar exterior to the point
where xmstar = mstar - M_center
density and temperature in cgs units


### dxdt_nuc_factor_multiplier ¶

Gradually rescale dxdt_nuc_factor. At each step, multiply dxdt_nuc_factor by dxdt_nuc_factor_multiplier, until reach new_dxdt_nuc_factor.

### eps_nuc_factor_multiplier ¶

Gradually rescale eps_nuc_factor. At each step, multiply eps_nuc_factor by eps_nuc_factor_multiplier until reach new_eps_nuc_factor.

### opacity_max_multiplier ¶

Gradually rescale opacity_max. At each step, multiply opacity_max by opacity_max_multiplier until reach new_opacity_max.

### steps_for_relax_fixed_L ¶

Gradually modify fixed_L_for_BB_outer_BC.

### max_surf_dq_multiplier ¶

Gradually rescale max_surface_cell_dq. At each step, multiply max_surface_cell_dq by opacity_max_multiplier until reach new_max_surf_dq.

### relax_tau_factor_after_core_C_burn ¶

relax_to_this_tau_factor = 1 puts outer cell at photosphere; can go much larger or much smaller to move surface in or out from photosphere.

dlogtau_factor changes log10(tau_factor) by at most this amount per step

relax_tau_factor true gradually changes tau_factor, reconverging at each step.

relax_tau_factor_after_core_He_burn ignored if <= 0; change tau_factor when center H1 < 1e-4 and center He4 < relax_tau_factor_after_core_He_burn.

relax_tau_factor_after_core_C_burn ignored if <= 0; change tau_factor when center H1 < 1e-4, He4 < 1e-4, and center C12 < relax_tau_factor_after_core_C_burn.

### set_tau_factor_after_core_C_burn ¶

As for relax_to_this_tau_factor, but changes tau_factor without reconverging.

if adjust_tau_factor_to_surf_density, then at start of each step set tau_factor to current Rho(1) divided by base_for_adjust_tau_factor_to_surf_density

### set_initial_Tsurf_factor ¶

As for relax_to_this_Tsurf_factor, but changes Tsurf_factor without reconverging.

### relax_mass_change_final_mdot ¶

relax_mass_change_max_yrs_dt in years relax_mass_change_init_mdot in Msun/year

extra heat near surface to model irradiation. relax_to_this_irrad_flux is flux in erg s^-1 cm^-2 from companion. we capture Pi*R^2 of that flux and distribute it uniformly in the outer 4*Pi*R^2*irrad_col_depth grams of the star, where irrad_col_depth is in g cm^-2.

as for relax_irradiation but sets values and does not reconverge

### new_lnPgas_flag ¶

lnPgas variables lnPgas_flag is true if we are using lnPgas variables in place of lnd

### new_RTI_flag ¶

RTI variables RTI_flag is true if we are doing Rayleigh Taylor Instabilities

## velocity variables ¶

### new_v_flag ¶

change whether MESA evolves a (radial) velocity variable, v, defined at cell boundaries

### center_ye_limit_for_v_flag ¶

automatically turn on velocities if center_ye drops below this limit. this is useful for evolution leading up to core collapse.

### gamma1_integral_for_v_flag ¶

automatically turn on velocities if center_gamma1_integral drops below this limit. this is useful for evolution leading up to pair instability core collapse. integral is sum over all cells of (gamma1-4d0/3d0) weighted by dm*P/rho

### new_u_flag ¶

change whether MESA evolves a (radial) velocity variable, u, defined at cell centers. this is an alternative to v at cell boundaries. can use one or the other, but not both.

Experimental – not ready for use.

## rotation controls ¶

### change_initial_rotation_flag ¶

rotation is enabled only if rotation_flag is true new_rotation_flag is only used if change_rotation_flag is true if change_rotation_flag true, then change rotation_flag to new_rotation_flag

NOTE: why 2 flags? because I want 3 options: set true, set false, and leave it alone. there are of course other ways to get 3 options, but this is what we have.

the following only apply when rotation is already on (i.e., when rotation_flag is true), including when you have just done change_rotation_flag true. all of these initialize the model to uniform omega (i.e. “solid body”)

### set_initial_omega ¶

new_omega in rad/sec set_omega applies when do ./rn or ./re; if true, sets uniform omega = new_omega set_initial_omega only applies at start of run, not for restarts if true, sets uniform omega = new_omega

### set_initial_omega_div_omega_crit ¶

as above, but sets omega/omega_crit omega_crit is defined as:

gamma_factor = 1d0 - min(L_div_Ledd, 0.9999d0)
omega_crit = sqrt(gamma_factor*s% cgrav(k)*s% m_grav(k)/pow3(s% r(k)))


### set_initial_surface_rotation_v = .false. ¶

as above, but sets surface velocity in km/sec

the previous controls are “one shot” – they set omega once and are done. however you might need to set omega for several models in a row in order to give things a chance to adjust to the change. the following controls let you do that.

### set_omega_step_limit ¶

if model_number is <= this, then do set_omega

### set_omega_div_omega_crit_step_limit ¶

if model_number is <= this, then do set_omega_div_omega_crit

### set_surf_rotation_v_step_limit ¶

if model_number is <= this, then do set_surface_rotation_v

### set_near_zams_surface_rotation_v_steps ¶

You might want to start a run at pre-ms but only turn on rotation when near zams rather than force you to stop the run near zams, change the inlist, and restart. The following will turn on rotation automatically. The working definition of “near zams” is L_nuc_burn_total/L_phot >= Lnuc_div_L_upper_limit Lnuc_div_L_upper_limit is in the controls part of the inlist.

The following apply when rotation is off and model satisfies the “near zams” test. Each turns on rotation and sets a step limit

only applies if > 0

set_omega_step_limit = model_number + set_near_zams_omega_steps - 1


only applies if > 0

set_omega_div_omega_crit_step_limit =
model_number + set_near_zams_omega_div_omega_crit_steps - 1


only applies if > 0

set_surf_rotation_v_step_limit =  model_number + set_surf_rotation_v_step_limit - 1


### num_steps_to_relax_rotation ¶

use num_steps_to_relax_rotation steps to relax omega to new value

### relax_omega_max_yrs_dt ¶

relax_omega_max_yrs_dt sets a maximum time step used during the relaxation process < 0 implies MESA chooses the step. Useful number is 1d4 if num_steps_to_relax_rotation > ~150

### near_zams_relax_omega ¶

if relax_omega true, relax to value of new_omega. applies when do ./rn or ./re relax_initial_omega only applies at start of run, not for restarts. near_zams_relax+omega applies when “near zams”. The working definition of “near zams” is L_nuc_burn_total/L_phot >= Lnuc_div_L_upper_limit Lnuc_div_L_upper_limit is in the controls part of the inlist.

### near_zams_relax_omega_div_omega_crit ¶

as above for relax_omega, but for omega/omega_crit

### near_zams_relax_initial_surface_rotation_v ¶

as above for relax_omega, but for surface speed

### use_D_omega_for_am_nu_rot ¶

if am_nu_rot_flag is true, use time and space smoothed am_nu_rot like D_omega else if D_omega_flag and use_D_omega_for_am_nu_rot, use D_omega for am_nu_rot else use am_nu_rot from current model with no smoothing

### core_avg_eps ¶

controls for nonzero center M (mass), R (radius), L (luminosity) (e.g., to model neutron star envelope or rocky core planet) new_core_mass in Msun units. If you have convergence problems, you’ll need to reduce the mass/step dlg_core_mass_per_step and timestep relax_core_years_for_dt values. core_avg_rho in g/cm^3 and core_avg_eps in ergs/g/sec are just examples. Adjust them to values appropriate for your application.

### relax_M_center_dt ¶

Like relax_mass_scale, but all change in mass goes into M_center. NOTE: new_mass is new total mass for star, not the new M_center value. uses dlgm_per_step in same way as relax_mass_scale. relax_M_center_dt in seconds

Example: If you want to end up with total mass = 1.4 and M_center = 1.3, start with star_mass = total - center = 0.1 = mass exterior to center. Then relax_M_center with new_mass = 1.4. That will give a new total mass of 1.4 by changing M_center. The mass exterior to the center will stay = 0.1, so the final M_center will be 1.3.

### relax_R_center_dt ¶

as above for the mass, but for the radius. new_R_center in cm. relax_R_center_dt in seconds.

### relax_v_center_dt ¶

new_v_center in cm/s. relax_v_center_dt in seconds.

### relax_L_center_dt ¶

as above for the mass, but for the luminosity. new_L_center in Lsun. relax_L_center_dt in seconds.

### remove_initial_center_by_infall_kms ¶

allows the core to be removed. ignored if <= 0 value for si28 is mass fraction at which to make mass cut i.e. cut at first location going inward where mass fraction of si28 >= this limit value for ye is electron per baryon number for cut value for infall_kms is infall speed in km per sec to make the cut

### remove_center_by_infall_kms ¶

allows the core to be removed. ignored if <= 0

### limit_center_logP_at_each_step ¶

at start of each step remove center cells if necessary to keep logP at innermost cell >= this limit.

### remove_initial_surface_by_v_surf_km_s ¶

allows the outer envelope to be removed. ignored if <= 0

### remove_surface_by_v_surf_km_s ¶

allows the outer envelope to be removed. ignored if <= 0

### repeat_remove_surface_for_each_step ¶

if true, then at each step removes surface as specified. e.g., if doing remove at specific density and expansion has lowered the surface density to below the limit, then remove surface mass down to the limit.

### report_mass_not_fe56 ¶

reports mass that is not fe56

### report_cell_for_xm ¶

in grams. if > 0 then write smallest k s.t. mass in cells 1 to k is >= report_cell_for_xm

### set_nzhi ¶

changes the composition to the mass fractions xa_for_accretion. useful for creating a model with specific uniform composition. set_to_xa_for_accretion true, means do when start or restart. set_initial_to_xa_for_accretion true, means do for start but not for restarts. nzlo and nzhi determine the range of cells that will be changed. nzlo < 0 means change out to surface. nzhi < 0 or nzhi > number of cells means change to center.

# eos controls ¶

### eosPT_Z1_suffix ¶

Modify this to select a different set of EoS tables.

### Z_part_PTEH ¶

If set_PTEH_Zs false, just use the eos default. Use full PTEH table for Z > Z_full_PTEH. Use partial PTEH table for Z < Z_part_PTEH. Blend in the region Z_part_PTEH < Z < Z_full_PTEH. This simply changes the corresponding values in the eos info.

### Z_all_OPAL ¶

Max Z for using tables instead of switching to HELM. If set_HELM_OPAL_Zs false, just use the eos default. Use HELM for Z > Z_all_HELM. Use OPAL for Z < Z_all_OPAL. Blend in the region Z_all_OPAL < Z < Z_all_HELM. The highest Z OPAL table in MESA is Z = 0.04.

### logT_low_all_SCVH ¶

Transition temperature zone for SCVH to HELM at low T. If set_HELM_SCVH_lgTs true, change limits.

• logT_low_all_HELM : use HELM for lgT <= this
• logT_low_all_SCVH : use SCVH for lgT >= this

### logT_all_OPAL ¶

Transition temperature zone for OPAL to HELM at high T. If set_HELM_OPAL_lgTs true, change limits.

• logT_all_HELM : use HELM for lgT >= this
• logT_all_OPAL : use OPAL/SCVH for lgT <= this

### logRho_min_OPAL_SCVH_limit ¶

Transition density zones for OPAL/SCVH to HELM/PC. If set_logRho_OPAL_SCVH_limits true, change limits.

• logRho1_OPAL_SCVH_limit : don’t use OPAL_SCVH for logRho > this
• logRho2_OPAL_SCVH_limit : full OPAL_SCVH okay for logRho < this
• logRho_min_OPAL_SCVH_limit : full HELM for logRho < this

Blend OPAL/SCVH with HELM/PC for logRho between these.

### PC_min_Z ¶

Change HELM PC limits. If set_eos_PC_parameters true, change limits.

• mass_fraction_limit_for_PC : skips species if abundance < this
• logRho1_PC_limit : use pure PC for logRho > this
• logRho2_PC_limit : don’t use PC for logRho < this (>= 2.8 or so because of PPT)
• log_Gamma_all_HELM : HELM for log_Gamma <= this (1.0d0 = log10(10))
• log_Gamma_all_PC : PC for log_Gamma >= this (1.3010299956d0 = log10(20))
• PC_Gamma_start_crystal : start releasing crystallization heat at Gamma > this
• PC_Gamma_full_crystal : finish releasing latent heat. Fully solid for Gamma > this
• PC_min_Z : don’t use PC for Z < this

Need PC_Gamma_start_crystal > Gamma_lnS_eps_grav_full_on for latent heat to be included in eps_grav properly.

### logT_ion_HELM ¶

HELM does not explicitly include ionization. Therefore these transitions are imposed manually.

Transition between neutral and ionized at some density Fully neutral for logRho <= max_logRho_neutral_HELM Fully ionized for logRho >= max_logRho_neutral_HELM

Transition between neutral and ionized over some temperature range Fully neutral for logT <= logT_neutral_HELM Fully ionized for logT >= logT_ion_HELM

### HELM_always_include_elec_pos ¶

Flags for controlling parts of HELM. If HELM skips electron-positron, it also skips coulomb. Together, this reduces HELM to doing an ideal gas eos. If you’d like to see what happens using an ideal gas for all cases, then set these controls:

set_other_HELM_flags = .true.
HELM_always_skip_elec_pos = .true.
HELM_always_include_elec_pos = .false.
HELM_include_radiation = .true. or .false. depending on what you want
set_HELM_OPAL_Zs = .true.
Z_all_HELM = -0.1 ! switch to HELM for Z > this
PC_min_Z = 1.1 ! don't use PC for Z < this


# nuclear reactions ¶

### change_initial_net ¶

For switching reaction networks. new_net_name only used if change_net if true.

If false, new isos initial abundance set to 0.

### new_rates_preference ¶

• 1 = NACRE rates
• 2 = jina reaclib rates

### set_rate_c12ag ¶

Empty string means ignore this control. Can be one of:

• ‘NACRE’
• ‘jina reaclib’
• ‘Kunz’
• ‘CF88’

(note: our CF88 is larger than the original by a factor of 1.7)

### set_rate_n14pg ¶

Empty string means ignore this control. Can be one of

• ‘NACRE’
• ‘jina reaclib’
• ‘CF88’

### set_rate_3a ¶

Empty string means ignore this control. Can be one of

• ‘NACRE’
• ‘jina reaclib’
• ‘CF88’
• ‘FL87’

FL87 is Fushiki and Lamb, Apj, 317, 368-388, 1987 and includes both strong screening and pyconuclear

### set_rate_1212 ¶

Empty string means ignore this control. Can be one of:

• 'CF88_basic_1212' : the single rate approximation from CF88.
• 'CF88_multi_1212' : combines the rates for the n, p, and a channels. c12(c12,n)mg23, c12(c12,p)na23, and c12(c12,a)ne20 and uses neutron branching from dayras, switkowski, and woosley, 1976.
• 'G05' : based on Gasques, et al. Phys Review C, 72, 025806 (2005)

Users can also provide tabulated rates for any of the reactions. Tabulated rates automatically take priority over any other options for the reaction. e.g., if you provide a rate table for c12ag, those rates will be used if preference to the other options given in set_rate_c12ag.

To provide tabulated rates: create a file of (T8, rate) pairs as in data/rates_data/rate_tables You can give as many pairs as you want with any spacing in T8. The first uncommented line of the file should be a number giving the total number of (T8, rate) pairs in the subsequent lines. The following lines are your specified values of T8 and rate separated by a single space, one pair per line. Add the filename to rate_list.txt along with the name of the rate you want it to govern, either in data/rates_data/rate_tables or in a local directory specified with the rate_tables_dir control. Be aware that if you choose to put the modified rate_list.txt in data/rates_data/rate_tables rather than a local directory, your custom tabulated rate will override the rate for that reaction for all future MESA runs.

If the reaction you wish to control does not already have a name that MESA will recognize, you will also need to add it to the file speficed by net_reaction_filename (defaults to reactions.list).
The default version of this file is located in data/rates_data. If you place a modified copy of this file in your work directory, it will take precedence.

### special_rate_factor ¶

For using other special rate factors. num_special_rate_factors must be <= max_num_special_rate_factors.

### co_net ¶

If auto_extend_net true, then automatically extend the net as needed from h_he_net to co_net and then to adv_net.

### min_x_for_n ¶

Heger-style adaptive network (Woosley, Heger, et al, ApJSS, 151:75-102, 2004). If enable_adaptive_network is true, then at each step, the system calculates a new set of isos according to the following rules:

for each iso in the current net:
let Z = number of protons in the iso and N = number of neutrons.
let x = max mass fraction for the iso in any cell in the model.
if x >= min_x_for_keep then include the iso in new net.
if x >= min_x_for_n then include following related isos:
(Z,N+1)   (Z,N-1)     -- add or remove neutron
if x >= min_x_for_add then include following related isos:
(Z+1,N)   (Z-1,N)     -- add or remove proton
(Z+2,N+2) (Z-2,N-2)   -- add or remove alpha
(Z+2,N+1) (Z-2,N-1)   -- exchange neutron/alpha
(Z+1,N+2) (Z-1,N-2)   -- exchange proton/alpha
(Z+1,N-1) (Z-1,N+1)   -- exchange proton/neutron
(Z+4,N+4) (Z+3,N+4)   -- extend alpha chain


Isos in the previous net can be dropped if they have x < min_x_for_keep and no other iso in the previous net causes them to be included in the new net. The new net has the included isos and all relevant reactions. The definition for the new net is saved to a text file in your local “nets” directory. The file name is composed of the model number and the number of species.

### net_reaction_filename ¶

Looks first in current directory, then in mesa_data_dir/rates_data.

### jina_reaclib_filename ¶

Empty string means use current standard version. Else give name of file in directory mesa/data/rates_data, e.g., jina_reaclib_results_20130213default2 (which is an 18.8 MB file of rates data). To use previous version, set to jina_reaclib_results05301331.

If you change reaclib version, you should clear the cache after making the change in order to ensure that cached rates from the default reaclib version are not being read. (You can use the script empty_caches in $MESA_DIR.) In order to avoid this caching issue, one can also specify a local rates cache directory via the control rates_cache_dir. ### jina_reaclib_min_T9 ¶ set jina reaclib rates to zero for T9 <= this. if this control is <= 0, then use the standard default from rates. need <= 3d-3 for pre-ms li7 burning if change this, must remove old cached rates from data/rates_data/cache ### rate_tables_dir ¶ When MESA looks for the files rate_list.txt and weak_rate_list.txt, it will look in a local directory with this name first. If doesn’t find one, it will use the one in data/rates_data/rate_tables. ### rate_cache_suffix ¶ If this not empty, then use it when creating names for cache files for reaction rates from rate_tables_dir. If empty, the suffix will be ‘0’. ### T9_weaklib_full_off ¶ ### T9_weaklib_full_on ¶ Weak rates blend weaklib and reaclib according to temperature. These can be used to overwrite the defaults in mesa/rates/public/rates_def • T9_weaklib_full_off : use pure reaclib for T <= this (ignore if <= 0) • T9_weaklib_full_on : use pure weaklib for T >= this (ignore if <= 0) ### weaklib_blend_hi_Z ¶ Ignore if <= 0. Blend for intermediate temperatures. For high Z elements, switch to reaclib at temp where no longer fully ionized. As rough approximation for this, we switch at Fe to higher values of T9. ### T9_weaklib_full_off_hi_Z ¶ ### T9_weaklib_full_on_hi_Z ¶ If input element has Z >= weaklib_blend_hi_Z, then use the following T9 limits: • T9_weaklib_full_off_hi_Z : use pure reaclib for T <= this (ignore if <= 0) • T9_weaklib_full_on_hi_Z : use pure weaklib for T >= this (ignore if <= 0) ## use small net for newton iterations only ¶ ### change_small_net ¶ ### new_small_net_name ¶ ### change_initial_small_net ¶ For switching reaction networks for use as small net in newton iterations. small net is only used when also doing split mixing. if small_net_name is empty string, then newton uses the standard net rather than the small one. new_small_net_name only used if change_small_net if true. ## controls for other weak rate sources ¶ ### use_suzuki_weak_rates ¶ If this is true, use the A=17-28 weak reaction rates from Suzuki, Toki, and Nomoto (2016) Electron-capture and$\beta\$-decay rates for sd-shell nuclei in stellar environments relevant to high-density O-Ne-Mg cores


If you make use of these rates, please cite the above paper.

### use_special_weak_rates ¶

If this is true, calculate special weak rates using the approach described in Schwab et al. (2015).

### special_weak_states_file ¶

File specifiying which states to include

Provide the low-lying energy levels of a given nucleus. These are needed to calcuate the partition function and to indicate which states have allowed transitions. Each isotope should have an entry of the form

<name> <nlevels>
<E_1> <J_1>
...
<E_n> <J_n>


where E = energy, J = spin.

### special_weak_transitions_file ¶

File specifying to include

These are the transitions for electron capture / beta decay reactions that should be used.

Each reaction should have and entry of the form

<iso1> <iso2> <ntrans>
<si_1> <sf_1> <logft_1>
...
<si_n> <sf_n> <logft_n>


where si / sf are the n-th parent / daughter state, counting in the order that you specified in the states file. logft is the comparative half-life of that transition.

### ion_coulomb_corrections ¶

select which expression for the ion chemical potential to use to calculate the energy shift associated with changing ion charge

• ‘none’: no corrections
• ‘DGC1973’: Dewitt, Graboske, & Cooper, M. S. 1973, ApJ, 181, 439
• ‘I1993’: Ichimaru, 1993, Reviews of Modern Physics, 65, 255
• ‘PCR2009’: Potekhin, Chabrier, & Rogers, 2009, Phys. Rev. E, 79, 016411

### electron_coulomb_corrections ¶

select which expression to use to calculate the shift in the electron chemical potential at the location of the nucleus

• ‘none’: no corrections
• ‘ThomasFermi’: Thomas-Fermi theory
• ‘Itoh2002’: Itoh et al., 2002, ApJ, 579, 380

# kap controls ¶

### kappa_config_file ¶

Modify this to provide alternative set of X,Z tables For Type1 high- and low-T opacities. This file is a namelist. Leave blank to use the defaults.

### kappa_file_prefix ¶

Modify this to select a different set of opacity tables. alternatives:

• 'gn93'
• 'gs98'
• 'a09'
• 'OP_gs98'
• 'OP_a09'

### kappa_lowT_prefix ¶

For lower temperatures. alternatives:

• 'lowT_Freedman11'
• 'lowT_fa05_gs98'
• 'lowT_fa05_gn93'
• 'lowT_fa05_a09p'
• 'lowT_af94_gn93'

### kappa_blend_logT_upper_bdy ¶

<= 0 means use default. Actual upper boundary will be min of this and max logT for lowT tables. it is probably a good idea to keep the blend away from H ionization. logT upper of about 3.9 or a bit less will do that. older version had default of 4.1 for kappa_blend_logT_upper_bdy.

### kappa_blend_logT_lower_bdy ¶

<= 0 means use default Actual lower boundary will be max of this and min logT for highT tables. typical logT_min for tables is 3.75. check your tables to be sure. older version had default of 4.0 for kappa_blend_logT_lower_bdy.

### kappa_type2_logT_lower_bdy ¶

<= 0 means use default Only use type2 opacities at temperatures above this limit.

### kappa_CO_prefix ¶

For C/O enhanced (Type 2 OPAL opacities). alternatives:

• ‘gn93_co’
• ‘gs98_co’
• ‘a09_co’

### use_IIp_opacities ¶

experimental. not yet part of public release.

### use_Ib_opacities ¶

experimental. not yet part of public release.

### kappa_min_logRho ¶

= 100 means use default in mesa/kap otherwise if actual logRho < this, clip and set partial wrt logRho to zero

# ionization controls ¶

### ionization_Z1_suffix ¶

Prefix and suffix of ionization files.

# "extra" parameters ¶

For use by your run_star_extras routines.

### extras_ipar ¶

extras_lipar number of integer parameters in extras_ipar. Must be <= max_extras_params (defined in run_star_support)

### extras_rpar ¶

extras_lrpar number of real(dp) parameters in extras_rpar. Must be <= max_extras_params (defined in run_star_support)

### extras_cpar ¶

extras_lcpar number of string parameters in extras_cpar. Must be <= max_extras_params (defined in run_star_support).

### extras_lpar ¶

extras_llpar number of logical parameters in extras_lpar. Must be <= max_extras_params (defined in run_star_support).

# Color Files ¶

### color_num_colors ¶

Filenames for each bolometric correction (BC) table to load
Must set the number of files to load
Must be <= max_num_color_files (defined in colors_def.f90).
Must set the number of BC's in each file (May be different for each file).
Must be <= max_num_bcs_per_file (defined in colors_def.f90).
Files should be structed as:
Teff log_g M_div_h filter1 filter2 ....
where filter1 is the name of the filter (No spaces allowed in name)
Names must be unique accross all files loaded and are case sensitive.
For a filter named filter1 history output will be bc_filter1 for bolometric corrections
and abs_mag_filter1 for absolute magnitude


Default file from Lejeune, Cuisinier, Buser (1998) A&AS 130, 65-75 Can be replaced if need be. The filter names are U B V R I J H K L Lprime M (case senistive)

Set of blackbody bolometric corrections in UBVRI Can be used at the same time as the lcb98cor.dat file Filter names bb_U bb_b bb_V bb_R bb_I color_num_files=2 color_file_names(2)=’blackbody_johnson.dat’ color_num_colors(2)=5

# misc ¶

### first_model_for_timing ¶

To get a breakdown of where the time is going set first_model_for_timing to determine when the clocks start. At the end of the run, there will be some output to the terminal showing times.

limit max timestep. If true, set max_timestep and max_years_for_timestep according to expected lifetime as a function of mass. Use the Iben & Laughlin (1989) formula to estimate lifetime. Multiply that times the value of max_frac_of_lifetime_per_step to get max_timestep.

### astero_just_call_my_extras_check_model ¶

Communications flag for astero and star.

# include other inlists ¶

You can split your star_job inlist into pieces using the following controls. BTW: it works recursively, so the extras can read extras too.

if read_extra_star_job_inlist{1..5} is true, then read &star_job from this namelist file
Due to changing the run_star_extras functions to hooks, we break existing run_star_extras files. This flag sets a warning message and stops the MESA run until it is set to .false.. This way people will hopefully not be confused as to why their run_star_extras functions are not being called.