Saturday, August 10, 2013

Luminosity Class

We just learned that when scientists want to measure how hot a star is,
they use something called stellar classification.

When they want to measure how bright a star is,
they use something called absolute magnitude.

Looking at both a star's temperature (heat) and it's luminosity (brightness),
scientists also come up with something called luminosity class or spectral classification.

Luminosity classes are named with both a number (roman numerals like you might see on a fancy clock)
and also a name, like a supergiant or subdwarf.

The luminosity classes from biggest to smallest are:
0 - hypergiants
I - supergiants
II - bright giants
III - normal giants
IV - subgiants
V - main-sequence stars (dwarfs)
VI - subdwarfs
VII - white dwarfs

luminosity class
(from: wikimedia - hertzsprung-russel diagram)