Reflection Nebula
A reflection nebula is a cloud of interstellar dust that becomes visible due to the light from nearby stars reflecting off its particles. Unlike emission nebulae, reflection nebulae do not emit their own light but shine by scattering the light of nearby stars.
Source: science.nasa.gov
APODs including "Reflection Nebula"
Star Clouds Toward the Southern Crown
02/10/2002
The flowing trails of dust toward Corona Australis, the constellation of the Southern Crown, are visible here not because they glow, but because they absorb and reflect. The dust appears bluer when seen near bright stars because it preferentially reflects blue light. The densest knots of dust are so thick that no background stars or interior stars can be seen through them. These knots indicate molecular clouds filled with cool gas where future stars will likely form. The above image spans about 5 degrees while the reflection nebula lies about 500 light-years distant.