Thus, the poles are "gravity brightened", and the equator "gravity darkened".

The star becomes oblate (and hence gravity darkening occurs) because the centrifugal force resulting from rotation creates additional outward pressure on the star. The centrifugal force is expressed mathematically as
: where is mass (in this case of a small volume element of the star), is the angular velocity, and is the radial distance from the axis of rotation. In