[Mesa-users] Molecular formation in EOS?

[Evan Bauer]

Hi Mutlu,

See also section 8.4 in MESA IV, Paxton et al. 2018.

The discussion there focuses mostly on ionization, but it also touches on molecular dissociation energy. The temperatures are not low enough for there to be any molecular hydrogen in the models shown in that section, but the dissociation energy still has to be accounted for to match the internal energy reported by the EOS. In particular, you can see that this energy is the dominant contributor to the internal energy for the neutral hydrogen at early time in figure 54 shown in that section.

Cheers,
Evan



> On Sep 6, 2018, at 2:16 AM, mutlu yildiz via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> Thanks! 
> 
> Section 4.3 and figure 2 in mesa I are for opacity. I have asked about molecular formation in EOS.
> 
> However, I have found the required explanations in Saumon et al. (1995, SCVH EOS). Hydrogen molecules are 
> taken into account...
> 
> Best Regards,
> 
> Mutlu
> 
> 
> On Thu, Sep 6, 2018 at 10:46 AM Francis Timmes <fxt44 at mac.com <mailto:fxt44 at mac.com>> wrote:
> see section 4.3 and figure 2 in mesa I, paxton et al 2011.
> 
> fxt
> 
> 
> 
> 
> > On Sep 6, 2018, at 12:24 AM, mutlu yildiz via Mesa-users <mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>> wrote:
> > 
> > Dear MESA users,
> > 
> > As you all know, molecules form in the cool outer regions of cool stars. Molecules are 
> > taken into account in the low-temperature opacities (Ferguson et al. 2005). However, I couldn't find 
> > any document about inclusion of molecules in MESA EOS. Is there any optional EOS for the  molecular formation? If not, maybe we can add a small subroutine for MESA EOS. 
> > 
> > Thank you for your help.
> > 
> > Best Regards,
> > 
> > Mutlu Yıldız
> > 
> > -- 
> > Prof. Dr.
> > Ege Üniversitesi Fen Fakültesi 
> > Astronomi UBB 35100 Bornova İzmir- Turkey
> > _______________________________________________
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> > 
> 
> 
> 
> -- 
> Ege Üniversitesi Fen Fakültesi 
> Astronomi UBB 35100 Bornova İzmir 
> _______________________________________________
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