[Mesa-users] Case B mass transfer at solar metallicity

[Ebraheem Farag]

Hello Debasish,

I'm guessing that by case B mass transfer you mean mass transfer which
occurs while the donor is in or evolving toward the Red Giant branch.
In that case I believe this is exactly what you are observing. You have a
system where M1 (donor) > M2 (BH) when mass transfer begins, as M1 evolves
to the RGB, the envelope expands, fills its Roche-lobe and begins stable
mass-transfer resulting in an increase in orbital separation until the
binary completely detaches ( mass-transfer approaches 0). The donor star
(M1) then continues its normal evolution, with wind driven mass-loss
stripping the remaining envelope, leaving as a hot exposed helium core at
helium depletion (a wolf-rayet star).

Hopefully this answers your question.

-EbF

On Sun, May 28, 2023 at 11:18 AM Debasish Dutta via Mesa-users <
mesa-users at lists.mesastar.org> wrote:

> Hi,
> I am trying to evolve a binary system with a black hole companion. I am
> interested in getting a Case B mass transfer. For lower metallicity models
> (SMC, LMC and Zsun/10), it seems to work well. However, for higher
> metallicity (~solar) massive models, I could not get the Case B mass
> transfer. I was using the initial orbital periods as 70 days for the lower
> metallicity models. In the case of solar metallicity, if I use an extended
> period (~450 days), I get some weird HR diagrams with the mass transfer
> phase almost non-existent. I  have attached my inlists and also a HR
> diagram of a 42 solar mass model at solar metallicity (mass ratio=0.6).
>
> I would be glad if someone could help me regarding this.
>
> Regards
> Debasish
> ᐧ
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