Brightness temperature

related topics
{math, energy, light}
{rate, high, increase}

Brightness temperature is the temperature a black body in thermal equilibrium with its surroundings would have to be to duplicate the observed intensity of a grey body object at a frequency ν. This concept is extensively used in radio astronomy and planetary science.

For a black body, Planck's law gives:

where

For a grey body the spectral radiance is a portion of the black body radiance, determined by the emissivity ε. That makes the reciprocal of the brightness temperature:

At low frequency and high temperatures, when h\nu \ll kT, we can use the Rayleigh–Jeans law:

so that the brightness temperature can be simply written as:


See also

Compare with color temperature and effective temperature.


Full article ▸

related documents
Guided ray
Édouard Roche
Umbra
Hour angle
Directive gain
Triangulum
Solid-state physics
Prandtl number
Gauss (unit)
Jerk
Angle excess
Alpha Arietis
Nereid (moon)
Zenith
Quintessence (physics)
Pseudosphere
Atom probe
Galactic coordinate system
433 Eros
Spica
Nichols radiometer
Equuleus
Camelopardalis
Icosidodecahedron
Thermosphere
Kirkwood gap
Rayleigh number
Field ion microscope
Microphotonics
Canes Venatici