Re: [mesa-users] Angular momentum loss due to winds

[Glenn-Michael O. <gle...@ku...>]

Note:

Subtracting b% mdot_wind_transfer(b% d_i)? should also do the trick.

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Van: Glenn-Michael Oomen
Verzonden: woensdag 12 juli 2017 11:09
Aan: mes...@li...
Onderwerp: Angular momentum loss due to winds


Hi Mesa,


There might be a small problem with how the loss of angular momentum due to stellar winds is computed. It appears to me that b% mdot_system_wind is not actually the mass lost due to stellar winds from the system, but the total wind mass loss.


So suppose I would for some reason impose a conservative wind mass transfer such that all the wind is transferred to the companion, then I would expect b% mdot_system_wind(b% d_i) to be zero, which is not the case. The bottom line is that this gives an overestimate for b% jdot_ml.


The issue is in line 290 (and 293) in binary_evolve.f90, where b% mdot_system_wind appears to be defined simply as the wind mass loss of the star. I think that the whole equation should be multiplied by (1 - b% wind_xfer_fraction(s_i)) as to account for wind mass transfer to the companion and vice versa.


Cheers,

Glenn-Michael Oomen