An Etymological Dictionary of Astronomy and Astrophysics

In the theory of → radiation-driven winds, an equation that describes the behavior of the → wind velocity of → hot stars as a function of distance from the star. This velocity β-law is given by the expression:

v(r) = v_∞(1 - R/r)^β, where v_∞ is the → terminal velocity, R is the stellar radius, and r the distance from the center. For → O-type stars, the exponent is estimated to be β = 0.8.

See also: → velocity; → law.