The Mass Function

How do the number of stars depend on their mass? That is, are most stars 1 Msun, 0.1 Msun, 10 Msun?

Look at the stars we see most easily in the sky. They span a wide range of mass from 0.5 - 10 Msun.

Look at the nearest stars to us. Most are low mass stars (0.5 - 1.0 Msun).

Which is a better estimate of the typical mass of stars?

We define something called the initial mass function, which describes the distribution of star masses which occur when stars form. It looks something like this: