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The **Planck function** is
a function of wavelength and temperature that
describes a distribution of the spectral
radiance at each wavelength in black-body radiation.

- B(ν,T) - spectral radiance (specific intensity).
- ν - wavelength.
- h - Planck constant.
- T - temperature.
- c - speed of light in a vacuum.
- k
_{B}- Boltzmann constant.

2hν^{3}1 B(ν,T) = ———— ——————————— c^{2}e^{hν/(kBT)}- 1

Radiance is the quantity of radiation emitted through a surface into a given solid angle, spectral radiance being the radiance at a given wavelength.

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

black-body radiation

brightness temperature (T

Rayleigh-Jeans law

Rosseland mean opacity

spectral signature

thermal emission

Wien approximation