[mesa-users] Angular momentum loss from mass loss clarification

[Kenny V. <kv...@ua...>]

Hi,

A question for clarity, in the binary_jdot.f90 the subroutine that
describes angular momentum loss from mass loss in the system is calculated
using:

         !mass lost from vicinity of donor

         b% jdot_ml = (b% mdot_system_transfer(b% d_i) + b%
mdot_system_wind(b% d_i))*&
             (b% m(b% a_i)/(b% m(b% a_i)+b% m(b% d_i))*b%
separation)**2*2*pi/b% period *&
             sqrt(1 - b% eccentricity**2)
         !mass lost from vicinity of accretor

         b% jdot_ml = b% jdot_ml + (b% mdot_system_transfer(b% a_i) + b%
mdot_system_wind(b% a_i))*&
             (b% m(b% d_i)/(b% m(b% a_i)+b% m(b% d_i))*b%
separation)**2*2*pi/b% period *&
             sqrt(1 - b% eccentricity**2)

ignoring the cct term.

I have a bit of confusion with the two mdot_system_transfer values. From
going through the code in the binary_mdot.f90 file it looks like

mdot_system_transfer(b% d_i)
describes the mass loss from the donor, where some percentage of this mass
(1- alpha) is just lost from the system.

mdot_system_transfer(b% a_i)
describes the mass that is lost from the donor and some percentage of this
is not accreted by the compact object and thus lost from the system.

Could someone verify this?

Thanks