Sednoid
Sign in to savethumb|upright=1.5|The orbits of the four known sednoids (colored pink). Their orbits are so distant that they never cross the Kuiper belt (shown in red). thumb|The apparent magnitudes of three of four known sednoids. thumb|Discovery image of Sedna (dwarf planet)|Sedna, the eponymous and first known sednoid
~9 min read
Article
7 sectionsContents
- Unexplained orbits
- Known members
- Theoretical population
- See also
- Notes
- References
- External links
thumb|upright=1.5|The orbits of the four known sednoids (colored pink). Their orbits are so distant that they never cross the Kuiper belt (shown in red). thumb|The apparent magnitudes of three of four known sednoids. thumb|Discovery image of Sedna (dwarf planet)|Sedna, the eponymous and first known sednoid
A sednoid is a trans-Neptunian object with a large semi-major axis, a distant perihelion and a highly eccentric orbit, similar to that of the dwarf planet Sedna. The consensus among astronomers is that there are only four objects that are generally agreed to belong to this population: Sedna, ("Biden"), 541132 Leleākūhonua, and ("Ammonite"). All four have perihelia greater than . The sednoids are also classified as detached objects, since their perihelion distances are large enough that Neptune's gravity does not strongly influence their orbits. Some astronomers consider the sednoids to be Inner Oort Cloud (IOC) objects. The inner Oort cloud, or Hills cloud, lies at 1,000–10,000 AU from the Sun.