Mass function
Mass function
**Mass function** may refer to:

* [Binary mass function](/wiki/Binary_mass_function "Binary mass function"), a function that gives the minimum mass of a star or planet in a spectroscopic binary system
* [Halo mass function](/wiki/Halo_mass_function "Halo mass function"), a function that describes the mass distribution of dark matter halos
* [Initial mass function](/wiki/Initial_mass_function "Initial mass function"), a function that describes the distribution of star masses when they initially form, before evolution
* [Probability mass function](/wiki/Probability_mass_function "Probability mass function"), a function that gives the probability that a discrete random variable is exactly equal to some value


What is the distribution of star masses when they initially form?