[Mesa-users] Question about modelling a star with neutron star at its core

[Bill Paxton]

Hi,

The effect of the TOV terms terms can be incorporated into the equations by modifying the local gravitational constant by means of the “other_cgrav” capability in mesa.

Here’s code that does that:


In the &controls section of your inlist, add this line

      use_other_cgrav = .true. ! for GR factor with gravity


I’ve run that in the current pre-release version, but not in the public one.   Let me know if you have problems getting it to work.

-Bill Paxton






> On Nov 13, 2020, at 6:43 AM, Sushovan Mondal via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> Hello everyone,
> 
> I am going through these instructions and trying to understand step by step. I have a question regarding the general relativistic effects near the neutron star core. In the original paper by Thorne and Zytkow (and later by others), the general relativistic effect is incorporated in the stellar structure. But the general relativistic effects (like TOV equations, and others) are not included in MESA. Can someone please guide me on how to incorporate general relativistic effects? 
> 
> Thanking you in advance,
> 
> Regards,
> Sushovan
> 
> On Sat, Nov 7, 2020 at 12:16 AM Francis Timmes <fxt44 at mac.com <mailto:fxt44 at mac.com>> wrote:
> one should walk through "getting started" 
> http://mesa.sourceforge.net/starting.html <http://mesa.sourceforge.net/starting.html>
> https://youtu.be/b0bZ9FAgyrg <https://youtu.be/b0bZ9FAgyrg>
> 
> and "using pgstar" 
> http://mesa.sourceforge.net/pgstar.html <http://mesa.sourceforge.net/pgstar.html>
> https://youtu.be/JZFa4WURztI <https://youtu.be/JZFa4WURztI>
> 
> and the "beyond inlists" mesa summer school material
> https://jschwab.github.io/mesa-2019/ <https://jschwab.github.io/mesa-2019/>
> 
> fxt
> 
> 
> 
> 
> > On Nov 6, 2020, at 10:58 AM, Sushovan Mondal via Mesa-users <mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>> wrote:
> > 
> > Dear Sir,
> > 
> > Thank you for your kind response. I have gone through the emails and it will help me a lot. As I am very new to MESA, so I have a very trivial doubt about the working process of MESA. I think there are various options available in the default files, and if I want to change those values then I have to make inlists to include those changes (otherwise the model will take the default values). Is this the way the process works? If I am wrong, please correct me. Is there any tutorial available for beginners? Though this is a very basic question, it will help me to understand the process better.
> > 
> > Thanks in advance,
> > 
> > Regards,
> > Sushovan
> > 
> > On Wed, Nov 4, 2020 at 7:58 PM Aaron Dotter <aaron.dotter at gmail.com <mailto:aaron.dotter at gmail.com>> wrote:
> > Hi Sushovan,
> > 
> > The answer is that there is no existing framework to make such an object but it may be possible to do.
> > 
> > There is a recent thread about this here:
> > 
> > https://lists.mesastar.org/pipermail/mesa-users/2020-August/011763.html <https://lists.mesastar.org/pipermail/mesa-users/2020-August/011763.html>
> > 
> > Please read through those emails and then come back to us if you have further questions.
> > 
> > Cheers,
> > Aaron
> > 
> > On Wed, Nov 4, 2020 at 9:13 AM Sushovan Mondal via Mesa-users <mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>> wrote:
> > Hello everyone,
> > 
> > I am a new user of MESA and trying to learn from MESA website. I want to model a star which has a neutron star at its core and a gaseous envelope (about the size of solar radius or more) over it (more or less like a Thorne Zytkow object). Is it possible to model this type of star in MESA? As I am new here, can someone please guide me how do I do that (or any specific tutorial available to handle this problem)?
> > 
> > Thanking you in advance,
> > 
> > Regards,
> > Sushovan
> > _______________________________________________
> > mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>
> > https://lists.mesastar.org/mailman/listinfo/mesa-users <https://lists.mesastar.org/mailman/listinfo/mesa-users>
> > 
> > _______________________________________________
> > mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>
> > https://lists.mesastar.org/mailman/listinfo/mesa-users <https://lists.mesastar.org/mailman/listinfo/mesa-users>
> > 
> 
> _______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users
> 

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