Tholin in the context of 145452 Ritona

Quaoar (minor-planet designation: 50000 Quaoar) is a ringed dwarf planet in the Kuiper belt, a band of icy planetesimals beyond Neptune. It has a slightly ellipsoidal shape with an average diameter of 1,100 km (680 mi), about half the size of the dwarf planet Pluto. The object was discovered by American astronomers Chad Trujillo and Michael Brown at Palomar Observatory on 4 June 2002. Quaoar has a reddish surface made of crystalline water ice, tholins, and traces of frozen methane.

Quaoar has two thin rings orbiting outside its Roche limit, which defied initial theoretical expectations that rings outside the Roche limit should be unstable. Quaoar has one moon named Weywot and another unnamed moon that has not yet been confirmed. It is believed that Quaoar's elongated shape, gravitational influence of its moons, and extremely cold temperature help keep its rings stable.

Makemake (minor-planet designation: 136472 Makemake) is a dwarf planet in the Kuiper belt, a disk of icy bodies beyond the orbit of Neptune. It is the fourth largest trans-Neptunian object and the largest member of the classical Kuiper belt, having a diameter 60% that of Pluto. It was discovered on March 31, 2005 by American astronomers Michael E. ("Mike") Brown, Chad Trujillo, and David Rabinowitz at Palomar Observatory. As one of the largest objects found by this team, the discovery of Makemake contributed to the reclassification of Pluto as a dwarf planet in 2006.

Makemake is similar to Pluto with respect to its surface: it is highly reflective, covered largely by frozen methane, and stained reddish-brown by tholins. Makemake has one known satellite, which has not been named. The orbit of this satellite suggests that Makemake's rotation has a high axial tilt, which implies that it experiences extreme seasons. Makemake shows evidence of geochemical activity and cryovolcanism, which has led scientists to suspect that it might harbor a subsurface ocean of liquid water. Gaseous methane has been found on Makemake, although it is unclear whether it is contained in an atmosphere or comes from temporary outgassing.

Sedna (minor-planet designation: 90377 Sedna) is a dwarf planet in the outermost reaches of the Solar System, orbiting the Sun far beyond the orbit of Neptune. It was discovered in 2003, and is roughly 1,000 km in diameter. Spectroscopic analysis has revealed its surface to be a mixture of the solid ices of water, carbon dioxide, and ethane, along with sedimentary deposits of methane-derived, reddish-colored tholins, a chemical makeup similar to the surfaces of other trans-Neptunian objects. Sedna is not expected to have a substantial atmosphere. Within the range of uncertainty, it is tied with Ceres in the asteroid belt as the largest dwarf planet not known to have a moon. Owing to its lack of known moons, Sedna's mass and density remain unknown.

Sedna takes approximately 11,400 years to complete one orbit around the Sun. Its orbit is one of the widest known in the Solar System. Its aphelion is located 937 astronomical units (AU) away, about 19 times farther than that of Pluto. Sedna's orbit is also one of the most elliptical discovered, with an eccentricity of 0.85. As of February 2025, Sedna is 83.2 AU (12.4 billion km) from the Sun, 2.5 times as far away as Neptune.

Quaoar (minor-planet designation: 50000 Quaoar) is a ringed dwarf planet in the Kuiper belt, a band of icy planetesimals beyond Neptune. It has a slightly ellipsoidal shape with an average diameter of 1,100 km (680 mi), about half the size of the dwarf planet Pluto. The object was discovered by American astronomers Chad Trujillo and Michael Brown at Palomar Observatory on 4 June 2002. Quaoar has a reddish surface made of crystalline water ice, tholins, and traces of frozen methane.

Quaoar has two thin rings orbiting outside its Roche limit, which defies theoretical expectations that rings outside the Roche limit should be unstable. Quaoar has one moon named Weywot and another unnamed moon that has not yet been confirmed. It is believed that Quaoar's elongated shape, gravitational influence of its moons, and extremely cold temperature help keep its rings stable.

The atmosphere of Titan is the dense layer of gases surrounding Titan, the largest moon of Saturn. Titan is the only natural satellite of a planet in the Solar System with an atmosphere that is denser than the atmosphere of Earth and is one of two moons with an atmosphere significant enough to drive weather (the other being the atmosphere of Triton). Titan's lower atmosphere is primarily composed of nitrogen (94.2%), methane (5.65%), and hydrogen (0.099%). There are trace amounts of other hydrocarbons, such as ethane, diacetylene, methylacetylene, acetylene, propane, PAHs and of other gases, such as cyanoacetylene, hydrogen cyanide, carbon dioxide, carbon monoxide, cyanogen, acetonitrile, argon and helium. The isotopic study of nitrogen isotopes ratio also suggests acetonitrile may be present in quantities exceeding hydrogen cyanide and cyanoacetylene. The surface pressure is about 50% higher than on Earth at 1.5 bars (147 kPa). This is higher than the pressure at the triple point of methane, which allows there to be liquid methane on the surface in addition to the gaseous methane in the atmosphere. The orange color as seen from space is produced by other more complex chemicals in small quantities, possibly tholins, tar-like organic precipitates.

10199 Chariklo /ˈkærəkloʊ/ is a ringed asteroid or centaur in the outer Solar System. It is the largest known centaur, with a diameter of about 250 km (160 mi). It orbits the Sun between Saturn and Uranus with an orbital period of 62.5 years. It was discovered on 15 February 1997 by the University of Arizona's Spacewatch project at Kitt Peak National Observatory. Chariklo has a dark, reddish surface composed of water ice, silicate minerals, amorphous carbon, and various complex organic compounds (also known as tholins).

Chariklo's ring system consists of two narrow rings of icy particles in orbit around the object. The rings of Chariklo were discovered in 2013, when astronomers observed Chariklo occulting or passing in front of a star. Chariklo was the first minor planet discovered to have rings, and as of 2025, it is one of the four minor planets known to have rings (the three others being 2060 Chiron, Haumea, and Quaoar). It is unknown what keeps Chariklo's rings stable, as it has been predicted that they should decay within a few million years. Astronomers have hypothesized that Chariklo's rings might be maintained by the gravitational influence of yet-undiscovered shepherd moons orbiting Chariklo. The origin of Chariklo's rings is uncertain, with various possible explanations including ejection of surface material via outgassing or tidal disruption of a moon around Chariklo.