[mesa-users] Hook in HR when hitting max_age

[Aaron Dotter]

Hi Radek,

I hope I can clear up some of the confusion:  You can safely use a09 for
high-T and a09p for low-T and maintain consistency.

The a09p in the low-temperature opacities is the standard Asplund et al.
2009 mixture based on photospheric abundances (as opposed to meteoritic).
 Here 'p' refers to photosphere, not Przybilla.  The reason for making a
choice in the low-T tables is that the low-T opacities include all the
elements H through U (or more?) whereas OPAL only 20 elements or so.  Some
of the elements cannot be measured in the solar spectrum; some can be
measured in the spectrum AND meteorites but the respective values differ
(esp. Li).  So one has to choose.  Since Li is irrelevant to OPAL, it makes
no difference.  It is unfortunate that there is some ambiguity in the names.

I have seen the small jump in the final (shorter) timestep in other codes
but I don't remember seeing it in MESA.  Can you say how long the final
timestep is?  And what if you increase the max_age somewhat, so that the
normal evolution goes beyond 4.57 Gyr?

Cheers,
Aaron





On Thu, Jan 30, 2014 at 8:09 PM, Radek Smolec <smolec at camk.edu.pl> wrote:

> Hi,
>
> I am also playing with solar calibration, but in a traditional approach,
> i.e. I modify Zini,Yini and alpha to match L, R (Teff) and Z/X at
> 4.57x10^years. I have two questions:
>
> When I use the stopping condition:
>  max_age = 4.57d9
> the last time step is adjusted to match the desired age. But in HR diagram
> it produces an artificial hook - see an example  Figure (magnified at the
> end of calculation) and inlist I used. The hook remains there for all the
> parameters I tried, sometimes it is smaller, sometimes it is very large.
> How can I get rid of it?
> (I am using 5819 so there should be no problems to reproduce it!)
>
> Second question, as you see in the inlist I am using A09 mix. But how to
> do it consistently?
>  There are no lowT opacity tables for A09. There are for A09p (A09 +
> Przybilla modifications), while for high temperatures we have a09 only.
> Also I have to set the initial_zfracs. Fortunately, these are for both A09
> and A09p, but none of the mixes can be used consistently. Has anyone played
> with low-temperature opacity tables with A09 and can share the tables? Now
> it seems that only with gn93/gs98 and OPAL the fully consistent
> calculations can be done (ie., we have gn93/gs98 for high temperature, low
> temperature and type-2 OPAL opacities).
> Cheers,
> Radek
>
>
>
> ------------------------------------------------------------------------------
> WatchGuard Dimension instantly turns raw network data into actionable
> security intelligence. It gives you real-time visual feedback on key
> security issues and trends.  Skip the complicated setup - simply import
> a virtual appliance and go from zero to informed in seconds.
>
> http://pubads.g.doubleclick.net/gampad/clk?id=123612991&iu=/4140/ostg.clktrk
> _______________________________________________
> mesa-users mailing list
> mesa-users at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/mesa-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20140130/359d3aad/attachment.html>