[mesa-users] irradiation

[Bill Paxton]

Hi Shih-Hsin,

I don't know if there is a "first prinicples" way to decide
on the value for column_depth_for_irradiation.
As a rule of thumb, you're looking for a value that is
small enough so that the energy is deposited in a region
of "not too large" optical depth (something < 10 for sure),
but at the same time large enough so that mesa can
deal with it (too tiny means it will try to deposit
all of the energy in one or two cells and that might
be tough for convergence.)   The test suite example
uses a column depth of 1 g cm^2 -- you might try that
and check to see the optical depth corresponding to that.

BTW: just a reminder to use
      kappa_file_prefix = 'gs98f'
so that you get the new Freedman low T opacities.

Also, you should know that there is another way
to deal with irradiated planets that uses a constant
pressure surface boundary condition following
Guillot & Havel, A&A 527, A20 (2011).
I haven't added a test_suite case for it yet (I'll do that soon!),
but let me know if you are interested in trying it
and I'll provide some more info for you.

Cheers,
Bill






On Jun 9, 2011, at 12:48 AM, 張世昕 wrote:

> Hi,
> 
> Two parameters are needed in the &controls namelist
> when the irradiation is involved.
> I could figure out the irradiation_flux, but don't know 
> how to determine the column_depth_for_irradiation (i.e. m_irradiation).
> 
> ex. 
> a planet (0.001Msun & atm=simple_photosphere) with a 3 day period 
> around a solar-type star. What's the column_depth_for_irradiation?
> 
> Thanks!!
> Shih-Hsin
> 
>