[mesa-users] Evolving a pre-CV

Bill Paxton paxton at kitp.ucsb.edu
Wed Jun 5 16:30:52 EDT 2013

On Jun 5, 2013, at 1:10 PM, Jaime Villaseñor wrote:

> Ok, great! Everything is working now as I wanted with the rlo test.
> Just two more questions: Where can I find the angular momentum loss equations that mesa uses?

The code lives in star/binary_systems/rlo_routines.inc

Our implementation was originally done with help from Saul Rappaport.
So you won't be surprised to learn that we use the "classic" scheme from
rappaport, verbunt, and joss.  apj, 275, 713-731. 1983.

You can find that plus the GR term and the term for mass ejected from the system
in the function "get_jdot".   There is even a term for tidal Jdot.

> and, what is the fr parameter in the 'inlist_rlo' file?

There are 4 cryptically named parameters that are used in setting timesteps.
They are specifying target per-timestep fractional changes for various things.

fm	-- fractional change in mass of envelope
fa	-- fractional change in binary separation
fr	-- fractional change in relative gap between R and RL, (RL-R)/R
fj	-- fractional change in angular momentum

here are the default values:
        fm = 0.01d0
        fa = 0.01d0
        fr = 0.05d0
        fj = 0.01d0


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