[Mesa-users] Requesting help Regarding Conservation of Mass during Evolution of LMXB

[Evan Bauer]

Hi Pulkit,

It looks like your eval_other_mdot_edd routine is setting mdot_edd_eta = 0.5, which is causing the accretor in your model not to retain all of the transferred mass even when the accretion rate isn't Eddington limited. See the comments here: https://docs.mesastar.org/en/release-r22.05.1/reference/binary_controls.html#use-radiation-corrected-transfer-rate <https://docs.mesastar.org/en/release-r22.05.1/reference/binary_controls.html#use-radiation-corrected-transfer-rate> 

You should be able to get rid of this behavior by setting
	limit_retention_by_mdot_edd = .false.
	use_other_mdot_edd = .false.

Hope that helps!

Cheers,
Evan

> On Oct 26, 2022, at 11:22 AM, Francis Timmes via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> hi pulkit,
> 
> the inlist_project and run_star_extras, with its own eval_mdot_edd_routine, is relatively complicated.
> my suggestion to help you resolve your issue is to simplify and bisect. for example, turn off all the 
> binary interaction controls. check that the total mass now remains constant. then add the binary interaction 
> controls one at a time until you identify the control that is causing the issue.
> 
> fxt
> 
> 
> 
> 
>> On Oct 23, 2022, at 4:36 AM, Pulkit Ojha via Mesa-users <mesa-users at lists.mesastar.org> wrote:
>> 
>> Dear All, 
>> 
>> I'm Pulkit and I'm trying to evolve LMXB containing a main sequence donor star of mass 1 Msun and a point mass of 1.35 MSun (specified as NS accretor) with an initial period of 1 - 1.5 days. While evolving binary systems, I'm facing some problems related to conservation of total mass during the evolution of LMXBs. Even if the mass transfer efficiency ( given by f_{mt} = 1 - \alpha - \beta - \delta ) is 1 by setting all the three parameters alpha, beta and delta to 0, the total mass of donor + NS is lost by 21%, i.e.  about 1.855 Msun mass remains finally. 
>> 
>> It has also been mentioned on the mesa document that "winds will carry specific angular momentum of stars even if the efficiency is 1". Since, alpha and beta are defined as "alpha = fraction of the mass lost from the vicinity of the donor as fast winds" and similarly beta for the accretor, they lead me to the question of what are the other kinds of winds which are not being controlled by these parameters.  
>> 
>> Hence, I would be really grateful if someone could help me understand the reason for mass not remaining conserved while evolving LMXBs.  For your reference, I'm attaching a zip file containing relevant inlist files. 
>> 
>> Yours Truly 
>> Pulkit
>> 
>> -- 
>> Pulkit Ojha
>> 5th Year Integrated MSc.,
>> School of Physical Sciences,
>> National Institute of Science Education and Research
>> Bhubaneswar, INDIA
>> 
>> 
>> 
>> <Pulkit_2022_LMXB.zip>_______________________________________________
>> mesa-users at lists.mesastar.org
>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>> 
> 
> _______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20221026/452aeb3f/attachment.htm>