Stars like Eta Carinae produce over a million times as much light as the Sun. They are quite rare — only a few dozen are present in a galaxy the size of the Milky Way. They are assumed to be near or over the Eddington limit. That means the outward pressure of their radiation is almost strong enough to counteract gravity. Stars over 120 solar masses exceed the Eddington limit, and their gravity is barely strong enough to hold in their radiation and gas.