亮度温度[Brightness Temperature] - 达人(其实～我是卧底，来自外星)

2005/11/15 | 亮度温度[Brightness Temperature]
类别(Ω〖物理〗) | 评论(0) | 阅读(125) | 发表于 20:21: The brightness temperature of a body is defined according to
(1)

where is the specific intensity and is given by the Planck Law. In radio astronomy, the Rayleigh-Jeans law can be used to approximate the Planck Law, so
(2)

where has MKS units of , is the frequency, k is Boltzmann's constant, T is the physical temperature, and c is the speed of light. Solving for then gives
(3)

(4)

where is the wavelength (Rybicki and Lightman 1979, p. 26; Thompson et al. 1986, p. 8; Janssen 1993, pp. 7-12). This can also be written in terms of the wavelength specific intensity by using
(5)

to obtain the relationship
(6)

Plugging back in then gives
(7)

(8); 0