Triton (moon)
Neptune's largest moon, captured from the Kuiper belt, with a retrograde orbit.
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Triton is Neptune's largest natural satellite and the only large moon in the Solar System with a retrograde orbit.[1] Triton hosts a thin, hazy atmosphere and is thought to have once been a dwarf planet captured from the Kuiper belt.[1]
Key facts and history
English astronomer William Lassell discovered Triton on October 10, 1846, just 17 days after Neptune was found.[2][3] Its orbit is nearly circular with an eccentricity of 0.000016.[4] The only close-up visit to Triton was the Voyager 2 flyby in 1989, which studied about 40% of its surface.[2] The moon has an unusually high albedo, reflecting 60–95% of sunlight, and its surface temperature is the coldest recorded in the Solar System at 38 K.[5]
To spot the moon, Lassell employed a reflecting telescope of his own construction, which had a 61 cm aperture and a metal mirror.[6] Camille Flammarion, in his 1880 publication Astronomie Populaire, was the first to suggest the name Triton.[7] Triton's path around Neptune is retrograde, meaning it travels in the reverse direction of Neptune's spin.[1] A single face of Triton is always directed toward Neptune because the moon is in synchronous rotation, a state known as tidal locking.[8]
Triton has a differentiated interior structure: an icy crust, a likely subsurface ocean, and a core composed of rock and metal.[4]
What the cited sources add
The study found both bodies have large amounts of nitrogen and trace methane and carbon monoxide, indicating they formed beyond the water-ice line.[9] A 2023 planetary science summer school report describes Triton's retrograde orbit as evidence it is a captured Kuiper belt object.[10] The Royal Observatory Greenwich records that Lassell's two-foot reflector telescope, used to discover Triton, was later donated to the observatory but proved an expensive disaster.[11] Mandt's team suggested that the early migration of the giant planets could have disturbed the orbits of objects like Triton, leading to its capture by Neptune.[9]
References
- Wikipedia, "Triton (moon)" (CC BY-SA 4.0), which cites: Overbye, "Bound for Pluto, Carrying Memories of Triton", New York Times, November 5, 2014; Chang, "Dark Spots in Our Knowledge of Neptune", New York Times, October 18, 2014; Agnor, "Neptune's capture of its moon Triton in a binary–planet gravitational encounter", Nature, 2006, p. 192–4 (original not read by us) en.wikipedia.org
- Wikipedia, "Triton (moon)" (CC BY-SA 4.0), which cites: "NASA Selects Four Possible Missions to Study the Secrets of the Solar System", NASA Jet Propulsion Laboratory (JPL); "Planetary Science Summer School · Jason Dekarske", Jason Dekarske, December 19, 2023 (we also read that source) en.wikipedia.org
- Wikipedia, "Triton (moon)" (CC BY-SA 4.0), which cites: Lassell, William, "Lassell's Satellite of Neptune", Monthly Notices of the Royal Astronomical Society, November 12, 1847, p. 8 (original not read by us) en.wikipedia.org
- Wikipedia, "Triton (moon)" (CC BY-SA 4.0), which cites: Williams, David R., "Neptunian Satellite Fact Sheet", NASA, November 23, 2006 (original not read by us) en.wikipedia.org
- Wikipedia, "Triton (moon)" (CC BY-SA 4.0), which cites: Medkeff, Jeff, "Lunar Albedo", Sky and Telescope Magazine, 2002; "12.3: Titan and Triton", October 7, 2016; "Triton: Neptune's Moon", January 2010; "Triton – NASA Science"; Nelson, R.M., "Temperature and Thermal Emissivity of the Surface of Neptune's Satellite Triton", Science, 1990, p. 429–431; McKinnon, "Encyclopedia of the Solar System", Elsevier, 2014, p. 861–882; Grundy, "Spectroscopy of Pluto and Triton at 3–4 Microns: Possible Evidence for Wide Distribution of Nonvolatile Solids", The Astronomical Journal, October 2002, p. 2273–227 en.wikipedia.org
- Wikipedia, "Triton (moon)" (CC BY-SA 4.0), which cites: "The Royal Observatory Greenwich – where east meets west: Telescope: The Lassell 2-foot Reflector (1847)", www.royalobservatorygreenwich.org; "The Royal Observatory Greenwich – where east meets west: Telescope: The Lassell 2-foot Reflector (1847)", www.royalobservatorygreenwich.org (we also read that source) en.wikipedia.org
- Wikipedia, "Triton (moon)" (CC BY-SA 4.0), which cites: Flammarion, Camille, "Astronomie populaire", 1880, p. 591; Moore, "The planet Neptune: an historical survey before Voyager", John Wiley & Sons, April 1996, p. 150 (see p. 68) (we also read that source) en.wikipedia.org
- Wikipedia, "Triton (moon)" (CC BY-SA 4.0), which cites: Davies, "A Control Network of Triton", J. Geophys. Res., 1991, p. 15675–15681 (original not read by us) en.wikipedia.org
- O'Callaghan, "Pluto and the largest moon of Neptune might be siblings", New Scientist, June 18, 2024. facts only, no text reused. newscientist.com
- "Planetary Science Summer School · Jason Dekarske", Jason Dekarske, December 19, 2023. facts only, no text reused. jasondekarske.com
- "The Royal Observatory Greenwich – where east meets west: Telescope: The Lassell 2-foot Reflector (1847)", www.royalobservatorygreenwich.org. facts only, no text reused. royalobservatorygreenwich.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Triton (moon) (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
More in Moons of Neptune
Elsewhere in Moons of Uranus and Neptune
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Triton (moon) (CC BY-SA 4.0).
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