Eris (67.78AU average from the Sun) is the largest known scattered disc object, and caused a debate about what constitutes a planet, because it is 25% more massive than Pluto [180] and about the same diameter. It is the most massive of the known dwarf planets. It has one known moon, Dysnomia. Like Pluto, its orbit is highly eccentric, with a perihelion of 38.2 AU (roughly Pluto's distance from the Sun) and an aphelion of 97.6 AU, and steeply inclined to the ecliptic plane at an angle of 44°. [181] a b c "Resolutions B5 and B6: 'Definition of a Planet in the Solar System' and 'Pluto' " (PDF). Resolutions adopted at the General Assemblies. International Astronomical Union. 2006. Archived (PDF) from the original on 6 January 2018 . Retrieved 9 April 2022. a b The mass of the Solar System excluding the Sun, Jupiter and Saturn can be determined by adding together all the calculated masses for its largest objects and using rough calculations for the masses of the Oort cloud (estimated at roughly 3 Earth masses), [43] the Kuiper belt (estimated at 0.1 Earth mass) [44] and the asteroid belt (estimated to be 0.0005 Earth mass) [45] for a total, rounded upwards, of ~37 Earth masses, or 8.1% of the mass in orbit around the Sun. With the combined masses of Uranus and Neptune (~31 Earth masses) subtracted, the remaining ~6 Earth masses of material comprise 1.3% of the total orbiting mass. Jaki, Stanley L. (1 July 1972). "The Early History of the Titius-Bode Law". American Journal of Physics. 40 (7): 1014–1023. Bibcode: 1972AmJPh..40.1014J. doi: 10.1119/1.1986734. ISSN 0002-9505. Archived from the original on 20 April 2022 . Retrieved 2 April 2022.

The four outer planets, also called giant planets or Jovian planets, collectively make up 99% of the mass known to orbit the Sun. [f] Jupiter and Saturn are together more than 400 times the mass of Earth and consist overwhelmingly of the gases hydrogen and helium, hence their designation as gas giants. [129] Uranus and Neptune are far less massive—less than 20 Earth masses ( M Earth) each—and are composed primarily of ice. For these reasons, some astronomers suggest they belong in their own category, ice giants. [130] All four giant planets have rings, although only Saturn's ring system is easily observed from Earth. The term superior planet designates planets outside Earth's orbit and thus includes both the outer planets and Mars. [89] Phillips, J. P. (1965). "Kepler's Echinus". Isis. 56 (2): 196–200. doi: 10.1086/349957. ISSN 0021-1753. JSTOR 227915. S2CID 145268784.

Quaoar (43.69AU average from the Sun) is the second-largest known object in the classical Kuiper belt, after Makemake. Its orbit is significantly less eccentric and inclined than those of Makemake or Haumea. [169] It possesses a ring system and one known moon, Weywot. [172]

where β g {\displaystyle \beta _{g}} = 27° 07′ 42.01″ and α g {\displaystyle \alpha _{g}} = 12h 51m 26.282s are the declination and right ascension of the north galactic pole, [231] whereas β e {\displaystyle \beta _{e}} = 66° 33′ 38.6″ and α e {\displaystyle \alpha _{e}} = 18h 0m 00s are those for the north pole of the ecliptic. (Both pairs of coordinates are for J2000 epoch.) The result of the calculation is 60.19°. Main articles: Asteroid belt and Asteroid Linear map of the inner Solar System, showing many asteroid populations Soviet spacecraft Vega 1 and Vega 2 and ESA spacecraft Giotto all made a flyby of Halley's Comet the year after, in 1986.Steffl, A. J.; Cunningham, N. J.; Shinn, A. B.; Stern, S. A. (2013). "A Search for Vulcanoids with the STEREO Heliospheric Imager". Icarus. 233 (1): 48–56. arXiv: 1301.3804. Bibcode: 2013Icar..223...48S. doi: 10.1016/j.icarus.2012.11.031. S2CID 118612132. cos ⁡ ψ = cos ⁡ ( β g ) cos ⁡ ( β e ) cos ⁡ ( α g − α e ) + sin ⁡ ( β g ) sin ⁡ ( β e ) {\displaystyle \cos \psi =\cos(\beta _{g})\cos(\beta _{e})\cos(\alpha _{g}-\alpha _{e})+\sin(\beta _{g})\sin(\beta _{e})} Plutoid chosen as name for Solar System objects like Pluto". Paris: International Astronomical Union. 11 June 2008. Archived from the original on 13 June 2008 . Retrieved 11 June 2008. First mixed gender crew aboard space station, and first woman, Svetlana Savitskaya, on space station. The Sun's Vital Statistics". Stanford Solar Center. Archived from the original on 14 October 2012 . Retrieved 29 July 2008, citing Eddy, J. (1979). A New Sun: The Solar Results From Skylab. NASA. p.37. NASA SP-402. Archived from the original on 30 July 2021 . Retrieved 12 July 2017.