[mesa-users] Status of OP_a09 tables?

[Ehsan Moravveji]

OK, so, I couldn’t resist to set up a test with the OP_a09 and OP Mono opacities to “try” to distinguish if this table was calculated using the AGSS09 solar photospheric composition or the bulk composition.
There are three attachments:
- Makefile
- comp_two_kap.f90: which is the executing program
- compare_kappa.f90: which is a small module that wraps around several public chem, kap and eos modules
This only works for AGSS09 for now.

in comp_two_kap.f90, you can specify your desired X, Z, logT and logRho.
I tried the following for the peak of the Iron bump (logT=5.2, logRho=-6.65) for the two suspected compositions, with a hope that the closest value of the OP_a09 tables to what OP Mono computes would allow discriminating between the two compositions. 
Here is a brief summary of the output:

Composition:     Photosphere                          Bulk
(X, Y, Z)             (0.7381, 0.2481, 0.0134)       (0.7154, 0.2703, 0.0142)
OP Mono           0.565                                     0.576
OP_a09             0.568                                     0.579

The difference between log_kappa from OP Mono and OP_a09 is 0.003 dex in both cases; damn …
So, I cannot still say whether the OP_a09 tables were computed with the photospheric or bulk composition.

I hope this helps so far.
If anybody has another idea to experiment with, please share your thoughts, and I would be happy to look deeper.

Cheers
Ehsan
 
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> On 27 Jul 2015, at 20:03, Bill Paxton <paxton at kitp.ucsb.edu> wrote:
> 
> 
> On Jul 27, 2015, at 9:37 AM, Warrick Ball wrote:
> 
>> So, in short, what's up with these tables?  Are they currently usable?  I ask for a comparison I'm making when modelling Sun-like solar-like oscillators, if there's some rho-T regime in which the tables are okay.
> 
> 
> Hi Warrick,
> 
> As with everything in MESA -- "Use at your own risk.  Check your results for sanity.  Trust nothing".   Perhaps things have changed, but back when I renamed those tables the "new improved" OP release did in fact sometimes produce NaNs for extreme values of (Rho,T) at the edge of the table range.  Since the results looked okay (to my untrained eye) away from the table edges, I didn't just remove the tables, instead I hand edited the output to replace the NaNs by a rough interpolation of the non-NaN neighboring results.   Hence the "nans_removed_by_hand" in the new file names.   Use them if you wish -- as long as your model stays away from the edges of the table you might be okay.
> 
> If you'd like to contact the OP folks to see if they have fixed the problem, please do so -- and then build some new tables for mesa!
> 
> Cheers,
> Bill
> 
> 
> 
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