Understanding White Dwarf Temperature

[piareround]

So after a long time I finally figured out how the white Dwarf classification system works.

Basically its first the letter D
Followed by a temperature


Correct me if I am wrong but, DO, DB, DC, DZ white dwarfs are associated with a specific effective temperature of the star. However, White dwarf stars are no precisely definable by their spectra. In fact, seems that DA and DQ actually overlap in temperature with the other spectral classifications in the table.

Therefor this got me wondering...

Is their even a known statistical relationship for DA white dwarf stars that relates their Temperature to the stars Mass, Luminosity, Radius, or any other stellar measurements?

If not then how to scientist measure the radius and mass of white dwarfs when they are like 50-100 pc away.

Please can some one help me out here >>;

 

[phyzguy]

Wikipedia is always a good place to start on topics like this:

http://en.wikipedia.org/wiki/White_dwarf

As far as measuring the properties, masses are usually measured by finding white dwarfs that are part of a binary system. Then from measuring the orbital dynamics, one can determine the masses of the two stars. Once the mass is known, there is a theoretical relationship between mass and radius (see above reference) that allows you to determine the radius. This can also be checked by measuring the luminosity and using the Stefan Boltzmann relation, together with the measured temperature, to calculate the radius.
I don't think there is a fundamental relationship between mass and temperature, as there is for main sequence stars. Since white dwarfs are no longer producing fusion energy, there are slowly cooling off. So their temperature also depends on how old they are.

 

[piareround]

Thanks PhyzGuy, I really appreciate the help with understanding this. ^^