Reflection nebulas reflect light from a nearby star.
Many small carbon
grains in the nebula reflect the light.
The blue color typical of reflection nebula is caused by blue light being
more efficiently scattered by the carbon
dust than red light.
The brightness of
the nebula is determined by the
size and density of the reflecting grains,
and by the color and brightness of the neighboring star(s).
pictured above, surrounds
(23 Tau), one of the brightest stars in the
The Pleiades nebulosity is caused by a chance encounter between an
open cluster of stars and a dusty