Change of Binary Parameters:
Mass, Semi-major Axis and
Eccentricity

As mentioned earlier, the duration of the binary evolutionary stage
(say, I+I) is determined by the faster evolving component
, where
is the time each component spends at the corresponding evolutionary stage.
On the other hand, based on the evolutionary considerations, we are able
to calculate how the mass of the faster evolving star should change (if
at all) (e.g. due to stellar wind or RL overflow), that is we know the
quantity
the leading (faster evolving) star loses. Thus, a characteristic mass loss
rate at this stage is

Next, we should calculate the mass change for the slower evolving companion,
the orbital semi-major axis and the eccentricity.