[mesa-users] stellar-structural noise

[Alfred Gautschy]

Warrick

>PS: Just to be specific, the relevant line in &controls is:
>cubic_interpolation_in_Z = .true. ! .false. by default 

Thanks for the hint. I checked that I am indeed on  
cubic_interpolation_in_Z = .true.
in the treatment of opacities. So, my problem is not related to the
opacities directly at least regarding Z-interpolation.

But since EoS is also tabular, I wonder what is done there with respect
to interpolating in Z. I cannot find any switches with respect to its
treatment of Z-interpolation though.

It was actually *your* PhD thesis which hinted to me that we might have
a tabular - i.e. coarse-grain EoS - problem here. As far as I remember,
the Cambridge stellar-evolution code always solves the Eggleton et al.
EoS directly at each location necessary and the UV diagrams in your
thesis are smooth like a peach. 

Regards, Alfred

> 
> I haven't given it much thought but are you using cubic interpolation in 
> the opacities?  I think it's enabled by default in X but not in Z.  I 
> don't know if that could be the problem but it is a grid-related option.
> 
> Cheers,
> Warrick
> 

> On Fri, 18 Oct 2013, Alfred Gautschy wrote:
> 
> > Aaron
> >
> > Thanks for the quick reply with the pointers to further playgrounds. I
> > am on the way to follow your suggestions an will be back when I have
> > results.
> >
> > For the moment just a quick answer on diffusion to inform also other
> > possible bystanders: NO DIFFUSION is included. I cut down on
> > astrophysical processes as much as possible to hopefully isolate the
> > source of evil at some point [if it should turn out not to be me ;-) ]
> >
> > Regards,
> > Alfred
> >
> >
> >
> >
> >
> >
> >
> 
> 
> ------------
> Warrick Ball
> Postdoc, Institut für Astrophysik Göttingen
> wball at astro.physik.uni-goettingen.de
> +49 (0) 551 39 5069