Object Analysis

The Iris Nebula (NGC 7023) is a bright reflection nebula in the constellation Cepheus. Unlike emission nebulae which glow red from ionized gas, reflection nebulae glow blue because they are composed of interstellar dust that scatters the light of nearby stars—similar to how our atmosphere scatters sunlight to make the sky blue.

The nebula is illuminated by a magnitude +7 star, SAO 19158, which lies at the center of the dust cloud. The nebula is located 1,300 light-years away and is six light-years across. The central region is incredibly bright, resembling a blossoming flower, hence the name "Iris."

Surrounding the bright blue center are thick, dark clouds of obscuring dust that contain complex carbon molecules. These dark regions are effectively "molecular fog," blocking the light of background stars and providing a stark contrast to the brilliant blue petals of the nebula.