wd_o_ne_3_phase

wd_o_ne_3_phase#

Tags: star white-dwarf oxygen-neon-white-dwarf phase-separation crystallization

This test case demonstrates the implementation of three-component phase separation in an ONeNa white dwarf (see Castro-Tapia & Cumming 2025).

Part 1 (inlist_create_wd) (optional) creates an 8.3 M⊙, Z = 0.02 metallicity pre-main-sequence star and evolves it to the end of the AGB phase. The result is a 1.1 M⊙ ONeNa white dwarf. Since this is a “sped-up” method for producing an O/Ne white dwarf, it is recommended to accrete some helium and/or hydrogen onto the surface of the resulting white dwarf to obtain a more accurate cooling model. Alternatively, any white dwarf model can be used as the input model.

Part 2 (inlist_wd_o_ne_3_phase) loads wd1_10_mi8_3_ONeNa.mod, a 1.1 M⊙ ONeNa white dwarf with a helium atmosphere, and evolves it until the core temperature drops below log10(T/K)=6.3.

Throughout the white dwarf cooling phase, phase separation occurs as a result of crystallization. With phase_separation_option = '3c', the three most abundant elements in the core that transition to the solid phase undergo fractionation, as predicted by ternary phase diagrams.

Example of the cooling before crystallization:

../_images/Grid2000200.png

Example with a portion of the core crystallized:

../_images/Grid2000450.png

pgstar commands used for the plots above:

&pgstar

file_white_on_black_flag = .true. ! white_on_black flags -- true means white foreground color on black background
file_device = 'png'            ! png
!file_device = 'vcps'          ! postscript

       Grid2_win_flag = .true.
       Grid2_win_width = 16
       Grid2_title = 'inlist_wd_o_ne_3_phase'
       Grid2_xleft = 0.08
       Grid2_xright = 0.99
       Grid2_ybot = 0.04
       Grid2_ytop = 0.92

       Grid2_file_flag = .true.
       Grid2_file_width = 16
       Grid2_file_interval = 50

       TRho_Profile_xmin = -6.0
       TRho_Profile_xmax = 8.5
       TRho_Profile_ymin = 3.0
       TRho_Profile_ymax = 9.5

       show_TRho_Profile_eos_regions = .true.
       show_TRho_Profile_degeneracy_line = .true.
       show_TRho_Profile_Pgas_Prad_line = .true.
       show_TRho_Profile_burn_lines = .true.
       show_TRho_Profile_burn_labels = .true.
       show_TRho_Profile_text_info = .false.
       TRho_Profile_title =' '

       Abundance_xaxis_name = 'logxm'
       Abundance_xaxis_reversed = .true.
       Abundance_xmin = -8.0
       Abundance_xmax = 0.4
       Abundance_log_mass_frac_min = -5.0
       Abundance_log_mass_frac_max =  0.3
       num_abundance_line_labels = 5
       Abundance_legend_max_cnt = 0
       Abundance_title =' '

       HR_title =' '
       TRho_title =' '

       pgstar_model_coord = 0.96

/ ! end of pgstar namelist

Last-Updated: 30Jul2026 (MESA 26.04.1) by mcastrotapia.