Scattered disc is a distant circumstellar disc in the Solar System. It is sparsely populated by icy small solar system bodies. The closest scattered-disc objects approach the Sun at about 30–35 AU. Their orbits can extend well beyond 100 AU, making them among the coldest and most distant objects in the solar System.
About Scattered disc in brief
Scattered disc is a distant circumstellar disc in the Solar System. It is sparsely populated by icy small solar system bodies. The closest scattered-disc objects approach the Sun at about 30–35 AU. Their orbits can extend well beyond 100 AU, making them among the coldest and most distant objects in the solar System. The innermost portion of the scattered disc overlaps with a torus-shaped region of orbiting objects traditionally called the Kuiper belt. A third reservoir of trans-Neptunian objects, the Oort cloud, has been hypothesized, although no confirmed direct observations have been made. The first object presently classified as an SDO to be discovered was 1995 TL8, found in 1995 by Spacewatch. As of 2011, over 200 SDOs have been identified, including Gǃkúnǁʼhòmdímà, 2002 TC302, Eris, Sedna and 2004 VN112. Although the numbers of objects in Kui per belt and scattered disc are hypothesized to be roughly equal, observational bias due to their greater distance means that far fewer SDO have been observed to date. Some researchers further suggest a transitional space between the scatteredDisc and the inner Oortcloud, populated with “detached objects”. The first scattered disc object to be recognised as such was 1996 TL66, originally identified in 1996 by astronomers based at Mauna Kea in Hawaii. Three more were identified by the same survey in 1999: 1999 CV118, 1999 CY118, and 1999 CF119.
Scattered disc objects come within gravitational range of Neptune at their closest approaches, but their farthest distances are many times that. Ongoing research suggests that the centaurs, a class of icy planetoids, can be disturbed by the gravitational perturbation of the planet Neptune. These objects are never close enough to Neptune to be scattered by its gravity. Those in 2: 3 resonance are known as Pluto plutinos because Pluto is the largest member of their group, whereas those in 1: 2 resonances such as 2: 2 are as small as 1:2. In contrast, in contrast to the KUIper belt, the scattered- Disc objects can be known as ‘twotinos’ because they lie in orbits untouched by Neptune, and those which Neptune has locked into a precise orbital ratio of 2 and 1: 1. These ratios, called orbital resonances, allow Neptune’s gravitational influence to persist in regions which would otherwise have cleared out over the age of the Solar system, since Neptune’s gravity would not have cleared them out. The scattered disc is thought to be the place of origin for most periodic comets in theSolar System. Some such as Sedna have sometimes been considered to be included in this group, and some such as Pluto have been considered as a ‘detached object’ by some researchers. Many objects of the proposed OortCloud are also thought to have originated in the scattered Disc.