[mesa-users] Using neu module

Josiah Schwab jwschwab at berkeley.edu
Wed Sep 28 20:13:10 EDT 2016

Hi Jonathan,

> Yes, sources is size (num_neu_types, num_neu_rvs) hen you can do a
> look up against the constants in the neu_def file to determine what
> each index is

Yes, as Rob says see neu_def.f and neu_lib.f in $MESA_DIR/neu/public/.

I'd encourage you to use those constants, and write things like

  sources(brem_neu_type, ineu)

> Second, assuming I'm correct in understanding the outputs, for some values
> of T and Rho, I'm getting negative loss rate due to bremsstrahlung
> neutrinos. For example, if I input T=23095520474 and Rho=20092329582, I get
> a brems loss rate of -79390045138215.922 ergs/g/s. This doesn't seem
> correct. Am I using the module outside normal operating conditions? Am I
> misunderstanding how the neutrinos subroutine in mod_neu works?

The fitting formulae are from Itoh et al. (1996).


In Sec. 5.1, which at a quick glance seemed like the relevant part, the
upper limits looked like logRho=12 and logT=11.

I just called Frank's sneut4 (which is essentially what is in MESA) at
roughly the same Rho and T and also got a negative number.


Smells like you're pushing things too far; that's certainly outside
where MESA usually gets called.  Maybe Frank can weigh in.

> I've attached a copy of the sample/src/sample.f I've used to produce the
> above result.

I don't think it matters here, but do note that z2bar is <z^2> and not <z>^2.


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