Sound Familiar?

                                                        I think you know the tune:

Twinkle Twinkle Little Star
I know exactly what you are

 Opaque ball of hot dense gas
Million times our planet's mass
Looking small because you're far
I know exactly what you are

Fusing atoms in your core
Hydrogen, helium, carbon and more
With such power you shine far
Twinkle twinkle little star

Bright when close and faint when far
I know exactly what you are
Smallest ones burn cool and slow
Still too hot to visit, though

Red stars dominate by far
Twinkle twinkle little star
Largest ones are hot and blue
Supernova when they're through

Then black hole or neutron star
I know exactly what you are
Forming from collapsing clouds
Cold and dusty gas enshrouds

Spinning, heating protostar
I know exactly what you are


Source ? : found at Reddit, where it was attributed to the Girl Scouts.

UPDATE 9/12/12: Our commenter Jason tells me that the author of this little gem is astronomer Julia Kregenow of Penn State University.