# The application of of Fermi Dirac statistics in the white dwarf

1. Jul 21, 2014

### clumps tim

hi guys, I wonder if I have fully understood the Fermi Dirac statistics properly, but I have a question on it regarding its application in the white dwarf research. I read the Fermi energy is applicable for T=0, now if the core of a white dwarf is too hot then how can we apply the Fermi Dirac statistics there to calculate the electron degeneracy ?

can you please explain me ?
regards

2. Jul 21, 2014

### Matterwave

The temperature of a white dwarf is certainly very hot compared to our regular every day standards, but it is low compared to the Fermi temperature $T_F\equiv \epsilon_F/k$ and so a white dwarf is highly degenerate and we *must* use the Fermi Dirac statistics and not Maxwell-Boltzmann statistics.

T=0 is used only as an approximation, it should really read $T<<T_F$ for practical applications. This of course means that the object of interest is not, strictly speaking, totally degenerate, but it is strongly degenerate.

3. Jul 22, 2014

### clumps tim

thanks a lot, now it makes sense