Limb darkening

(The limb darkened Sun - An image of the Sun in visible light showing the limb darkening effect as a drop in intensity towards the edge or "limb" of the solar disk.)

Limb darkening refers to the diminishing of intensity in the image of a star as one moves from the center of the image to the edge or "limb" of the image. Limb darkening occurs as the result of two effects:

• The density of the star diminishes as the distance from the center increases

• The temperature of the star diminishes as the distance from the center increases.