[WIP] Adding new alternate neutrino cooling first draft

[khanakbhargava]

This is the first draft of a neutrino cooling routine using the kippenhahn et al. approximations. I have used autodiff. I will compare these with itoh et al and give the options to choose between the two.

[khanakbhargava]

The pair annihilation approximations only account for T9 < 1 and T9 > 3. We need to find a way to blend the two. The book does not say anything about the temp in between.

[yut23]

Quick and dirty plot of the pair annihilation asymptotics (relevant page from archive.org):

[zingale]

see page 2 of Stans notes here:
https://www.ucolick.org/~woosley/ay220-15/lectures/lecture11.4x.pdf

[zingale]

Also, Clayton Eq 3-302 has the expression for T_9 < 1 as 4.9e18 -- I wonder if K&W have a typo and dropped the "1" in the "18" exponent?

[khanakbhargava]

docs build check is failing right now, but I fixed the rest issues.

[khanakbhargava]

This plot shows the neutrino cooling rate w.r.t temperature. I need to check what is happening at the lower temperatures.

[zingale]

this source discusses some new approximations:
https://www.sciencedirect.com/science/article/pii/S0550321303001512#BIB023