METISSE with BSE

BSE (Hurley et al. 2002) is a rapid binary evolution code that models key binary interaction processes such as mass transfer, common-envelope evolution, and supernovae. The algorithms implemented in BSE have served as the foundation for many subsequent rapid and detailed binary evolution codes.

Folow these steps to use METISSE with BSE:

1. Get the METISSE-enabled version of BSE through its GitHub repository.

   $ git clone https://github.com/poojanagrawal/BSE-METISSE
   $ git submodule update --init --recursive
   

   Alternatively, you can clone BSE and METISSE together:

   $ git clone --recurse-submodules https://github.com/poojanagrawal/BSE-METISSE.git
   

2. Compile the code using:

   $ ./mk
   

3. Let us compute the evolution of a single binary using BSE-METISSE, say a 2.5 M star with a 1 M companion, with an initial orbital period of 100 days in a circular orbit for the evolution time of 13.7 Gyr.

   When using BSE, METISSE-specific inputs are read through the METISSE_input_controls inlist in the evolve_metisse.in file. (See METISSE input controls for a complete list of input options).

   Important

   When using BSE, the file evolve_metisse.in should be located in the same directory as the bse executable.

   We supply the location of the folders containing Metallicity File for hydrogen and helium stars through METALLICITY_DIR and METALLICITY_DIR_HE. (Make sure to provide relevant paths based on the location of these folders on your machine ).

   &METISSE_input_controls
   
   METALLICITY_DIR = '/Users/poojan/Downloads/sample_tracks_solarZ/Hydrogen/'
               
   METALLICITY_DIR_HE = '/Users/poojan/Downloads/sample_tracks_solarZ/Helium/'
   
   verbose = .true.
   
   /
   

   All other inputs including the binary parameters as well as the values of mass and metallicity are read through the BSE input file binary.in.

   A typical binary.in looks like:

   2.5  1.0 13700 100  1 1 0.02 0.0     ! mass1 mass2 maximum_evolution_time orbital_period_in_days initial_type1 initial_type2 metallicity eccentricity
   0.5 0.0 1.0 3.0 0.5                   ! reimers_eta binary_wind_enhancement helium_star_mass_loss_factor alpha_common_envelope lambda_common_envelope
   0 1 0 1 0 2 3.0 29769                 ! common_envelope_flag tides_on_off white_dwarf_initial_final_mass_relation white_dwarf_cooling black_hole_kicks neutron_star_remnant_mass max_neutron_star_mass kick_random_seed
   0.001 0.01 0.02                        ! timestep_pts1 timesteps_pts2 timestep_pts3
   0.0 0.125 1.0 1.5 0.001 10.0 -1.0     ! kick_velocity_dispersion beta_wind_velocity xi_wind_accretion bondi_hoyle_wind_accretion_factor fraction_of_accreted_matter_retained_in_nova_eruption eddington_limit_factor gamma_angular_momentum_loss
   1                                      ! sse_flag
   

4. Run BSE using:

   $ ./bse_metisse
   

5. BSE will produce the following terminal output:

   METALLICITY_DIR: /Users/poojan/Downloads/sample_tracks_solarZ/Hydrogen
   
   METALLICITY_DIR_HE: /Users/poojan/Downloads/sample_tracks_solarZ/Helium
   
   Input Z is :  2.00000E-02
   Reading naked helium star tracks
   Found matching Z_files   2.00000E-02
   Found           33  tracks.
   Minimum initial mass    0.4
   Maximum initial mass  148.8
   Reading main (hydrogen star) tracks
   Found matching Z_files   2.00000E-02
   Found           85  tracks.
   Minimum initial mass    0.1
   Maximum initial mass  299.3
       TIME      M1       M2   K1 K2        SEP    ECC  R1/ROL1 R2/ROL2  TYPE
       0.0000    2.500    1.000  1  1      137.608  0.00   0.028   0.021  INITIAL 
   567.7662    2.499    1.000  2  1      137.650  0.00   0.064   0.022  KW CHNGE
   574.3388    2.499    1.000  3  1      137.653  0.00   0.120   0.022  KW CHNGE
   580.8607    2.499    1.000  4  1      136.164  0.00   0.524   0.022  KW CHNGE
   773.6237    2.496    1.000  5  1      136.255  0.00   0.295   0.022  KW CHNGE
   782.8053    0.426    1.000 11  1      132.493  0.00   0.000   0.015  KW CHNGE
   9515.7256    0.426    1.000 11  2     1856.760  0.00   0.000   0.002  KW CHNGE
   11250.9990    0.426    0.999 11  3     1857.020  0.00   0.000   0.002  KW CHNGE
   12178.6533    0.426    0.947 11  4     1927.083  0.00   0.000   0.149  KW CHNGE
   12308.4219    0.426    0.935 11  5     1942.590  0.00   0.000   0.023  KW CHNGE
   12317.3174    0.426    0.914 11  5     1973.257  0.00   0.000   0.059  BEG SYMB
   12317.3223    0.427    0.425 11 11     2795.724  0.00   0.000   0.000  KW CHNGE
   13700.0000    0.427    0.425 11 11     3755.136  0.00   0.000   0.000  MAX TIME
   

   For more detailed output, check the output file in the output_binary folder.

   As in the standalone mode, z_accuracy_limit can be adjusted in METISSE_input_controls to use nearby metallicity value if the required value is not present in the grid. See If the metallicity value is not present in the input grid for details.