[mesa-users] resending - Questions about physical model and numerical implementation of binary star evolution

[Bill Paxton]

On Dec 10, 2014, at 3:28 PM, 이현택 wrote:

> What is the computational implementation of Roche lobe?
> 


We make the usual simplifying assumption of a sphere with same volume -- using Eggleton's recipe.

Here's the routine that computes the Roche lobe radius (in binary/private/binary_evolve.f)

      real(dp) function eval_rlobe(m1, m2, a) result(rlobe)
         real(dp), intent(in) :: m1, m2, a
         real(dp) :: q
         q = pow_cr(m1/m2,one_third)
      ! Roche lobe size for star of mass m1 with a
      ! companion of mass m2 at separation a, according to
      ! the approximation of Eggleton 1983, apj 268:368-369
         rlobe = a*0.49d0*q*q/(0.6d0*q*q + log1p_cr(q))
      end function eval_rlobe


-Bill



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