[Mesa-users] Does it need to consider convection when relaxing entropy?

[曾耀田]

Dear all,

    I‘m trying to import a 3D He star model which was obtained from an SPH simulation into MESA. Like said in the MESA IV paper (Appendix B), I'm trying to use the relaxation process to achieve this purpose. I'm using the latest version of MESA (r12778). When relaxing composition I found it can work only num_steps_to_relax_composition = 500 . At the end of the relaxing composition, the age_yr is increased to 4d47 yrs. Is this reasonable? And during relaxing entropy, the luminosity profile appeared strange so I try to figout why.  I found when mixing_length_alpha = 0.0 or min_T_for_acceleration_limited_conv_velocity = 0d0 is set in the inlist, these strange place in the luminosity profile disappears. it seems the convection exists during the relaxing entropy. This seems to be inconsistent with the description of relax entropy in the mesa document (maybe my understanding is wrong). So now, I’m not sure whether or not the convection should be considered during relaxing entropy. Is there anyone who can help?




With best wishes,

Yaotian Zeng




The  inlist I used is shown below.


! inlist_relax

&star_job


    set_initial_dt = .true.
    years_for_initial_dt = 1d-4


    show_log_description_at_start = .true.
    show_net_species_info = .true.
    
    set_initial_cumulative_energy_error = .true.
    new_cumulative_energy_error = 0d0


    ! Relaxes composition
    relax_initial_composition = .true.
    num_steps_to_relax_composition = 500
    relax_composition_filename = "composition.dat"
    
    relax_initial_entropy = .true.
    max_steps_to_relax_entropy = 1000
    timescale_for_relax_entropy = 1d-9 ! in years
    max_dt_for_relax_entropy = 1d-9 ! in years
    num_timescales_for_relax_entropy = 300
    relax_entropy_filename = "entropy.dat"
    get_entropy_for_relax_from_eos = 'eosDE'


    save_model_when_terminate = .true.
    save_model_filename = 'relaxed.mod'


    save_pgstar_files_when_terminate = .true.
    pgstar_flag = .true.


/ ! end of star_job namelist


&controls


    !min_T_for_acceleration_limited_conv_velocity = 0d0

    initial_mass = 1.232d0

    !use_ledoux_criterion = .true.
    !mixing_length_alpha = 1.8
    !mixing_length_alpha = 0.0

    max_num_profile_models = 10
    profile_interval = 1
    history_interval = 1
    terminal_interval = 1
    write_header_frequency = 1


  ! stop when the center mass fraction of h1 drops below this limit
    ! max_age = 1d1
    xa_central_lower_limit_species(1) = 'he4'
    xa_central_lower_limit(1) = 1d-4


/ ! end of controls namelist


&pgstar


      
/ ! end of pgstar namelist

 
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