[Mesa-users] Obtaining information inside __extras.f90 to use for a custom hook

James Munday james.munday98 at gmail.com
Fri Feb 4 14:18:23 UTC 2022

Hi all,

I'm struggling to obtain the information I want when setting a custom hook
(setting use_other_jdot_ml = .true. in the binary controls).

For what I want to set it to, I need the mass transfer rate (b%
mtransfer_rate or similar), the masses of the stars at every step and the
orbital angular momentum, Jorb, at every step. When accessing it, the value
of b% mtransfer_rate is of the order of ~10^17 for a transfer of 10^-9
solar masses in pgplot/terminal.

Trying b% m1 and b% m2 just gives what the masses were initialised to be in
solar masses in inlist_project, and their units and magnitude are not
consistent with this mtransfer_rate value - I would like the current m1 m2.
To get Jorb, it is printed in the terminal and log, but I'm not sure how to
access that live either. I can get b% jdot_gr or b% jdot_ml fine, which are
identical values to those output in the terminal.

So the options are:
- Obtain all values in units that are consistent with b% mtransfer_rate
and compute jdot_ml
- Obtain all values in the format of those output in terminal and compute

Would someone please give me a point in the right direction for how to do
either of these options? My subroutine is attached below with comments for
the desired steps.

Ultimately, I'm trying to get
jdot_ml_term = Jorb * SQRT(rh*(1.0+mass1/mass2)) * mdot/mass1 ; with rh a
function of mass1 and mass2 only.

Many thanks in advance for any help,

      subroutine jdot_extra_jdot_routine(binary_id, ierr)
         integer, intent(in) :: binary_id
         integer, intent(out) :: ierr
         double precision :: mass1, mass2, jdot_ml_term, rh, mdot
         type (binary_info), pointer :: b
         ierr = 0
         call binary_ptr(binary_id, b, ierr)
         if (ierr /= 0) then
            write(*,*) 'failed in binary_ptr'
         end if

         mass1 = b% m1 !* m1 here is the donor
         mass2 = b% m2
         !masses above only get the initial mass (in solar masses) set in
inlist_project, not the current mass from star. think I want to access
something in s%
         rh = 0.0883 + 0.04858*LOG10(mass2 / mass1) + 0.11489*LOG10(mass2 /
mass1)*LOG10(mass2 / mass1) - 0.020475*LOG10(mass2 / mass1)*LOG10(mass2 /
mass1)*LOG10(mass2 / mass1)

         mdot = b% mtransfer_rate

         jdot_ml_term = SQRT(rh*(1.0+mass1/mass2)) * mdot/mass1 ! * Jorb <-
this is needed

         ! WANT   Jdot_ml_term = Jorb * SQRT((1+mass1/mass2) * rh ) * mdot
/ mass1
         ! to do this, want the value of M1 and M2 at each step
         ! and the current Jorb

         Overall for a run, values have (from reading terminal, mass
binary_step      M1+M2      separ       Porb          e      M2/M1
pm_i    donor_i    dot_Mmt        eff       Jorb      dot_J    dot_Jmb
      lg_dt         M1         R1         P1      dot_e      vorb1
 RL1    Rl_gap1     dot_M1   dot_Medd      spin1    dot_Jgr    dot_Jls
     age_yr         M2         R2         P2       Eorb      vorb2
 RL2    Rl_gap2     dot_M2      L_acc      spin2    dot_Jml  rlo_iters

bin     540   0.891000   0.093317   0.003498  0.000E+00   3.665089
 2          1 -1.667E-09   0.942808  2.614E+50 -1.082E+37  0.000E+00
   2.125646   0.190993   0.025569   0.000000  0.000E+001060.298005
0.025568  3.888E-05 -1.667E-09  2.702E-08  0.000E+00 -1.082E+37  0.000E+00
 1.0624E+07   0.700007   0.000000   0.000000 -2.717E+48 289.296627
0.046074 -1.000E+00  1.572E-09  5.399E+36  0.000E+00 -2.419E+32          5
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