An Etymological Dictionary of Astronomy and Astrophysics

An empirical power-law relation representing the number of clusters as a function of their mass. It is defined as: N(M)dM ∝ M ^-αdM, where the exponent α has an estimated value of about 2 and dM is the mass interval. It is believed that this is a universal law applying to a variety of objects including globular clusters, massive young clusters, and H II regions.

See also: → cluster; → mass; → function.