Are stars considered black bodies?

[werner heisenberg]

Can somebody answer my question in a unique word? Are stars considered black bodies?

 

[matt.o]

the spectrum of a star is approximately black body.

 

[werner heisenberg]

What does 'aproximately' mean? does any 'competely' black body exist somewhere or all black bodies are aproximately black bodies?

 

[matt.o]

approximately means not exactly. the cosmic microwave background is better approximated by a black body than a star. Hawking radiation, although not yet observed, is also black body.

I don't think there exists any "perfect" black body.

 

[SpaceTiger]

What does 'aproximately' mean? does any 'competely' black body exist somewhere or all black bodies are aproximately black bodies?

Blackbodies are a limiting case of thermodynamics. In that equilibrium calculations only truly apply in the limit of an infinite number of particles settling for an infinite amount of time, no blackbody will be perfect. However, the primary "imperfections" in most blackbody spectra are of a larger magnitude than this. In the case of stars, the imperfections are mostly absorption lines from the gas sitting above the photosphere.