Dust disc



A dust disc or debris disk is a circumstellar disk of dust and debris in orbit around a star. Sometimes these disks contain prominent rings, as seen in the image of Fomalhaut on the right. Debris disks have been found around both mature and young stars, as well as at least one debris disk in orbit around an evolved neutron star. Younger debris disks can constitute a phase in the formation of a planetary system following the protoplanetary disk phase, when terrestrial planets may finish growing. They can also be produced and maintained as the remnants of collisions between planetesimals, otherwise known as asteroids and comets.

Many stars throughout the known universe possess a debris disk. Long range, they are usually discovered by examining the star system in infrared light and looking for an excess of radiation beyond that emitted by the star. This excess is radiation from the star that has been absorbed by the dust in the disk, then re-radiated away as infrared energy.

Debris disks are often described as massive analogs to the debris in the Sol System. Most known debris disks have radii of 10–100 astronomical units (AU); they resemble Terra’s Kuiper belt in the Sol System, but with much more dust. Some debris disks contain a component of warmer dust located within 10 AU from the central star. This dust is sometimes called exozodiacal dust by analogy to zodiacal dust in Sol System.

