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The minor planet and centaur 10199 Chariklo, with a diameter of about , is the smallest object with rings and the fifth ringed object ever discovered in the Solar System.〔 Orbiting Chariklo is a bright ring system consisting of two narrow and dense bands, 6–7 km (4 mi) and 2–4 km (2 mi) wide, separated by a gap of .〔〔 The rings orbit at distances of about from the centre of Chariklo, a thousandth the distance between Earth and the Moon. The discovery was made by a team of astronomers using ten telescopes at various locations in Argentina, Brazil, and Chile in South America during observation of a stellar occultation on 3 June 2013, and was announced on 26 March 2014.〔 The existence of a ring system around a minor planet was unexpected because it had been thought that rings could only be stable around much more massive bodies. Ring systems around minor bodies had not previously been discovered despite the search for them through direct imaging and stellar occultation techniques.〔 Chariklo's rings should disperse over a period of at most a few million years, so either they are very young, or they are actively contained by shepherd moons with a mass comparable to that of the rings.〔〔〔 The team nicknamed the rings Oiapoque (the inner, more substantial ring) and Chuí (the outer ring), after the two rivers that form the northern and southern coastal borders of Brazil. A request for formal names will be submitted to the IAU at a later date.〔 It was proposed in January 2015 that 2060 Chiron has a similar pair of rings.〔 == Discovery == Chariklo is the largest confirmed member of a class of small bodies known as centaurs, which orbit the Sun between Saturn and Uranus in the outer Solar System. Forecasts had shown that, as seen from South America, it would pass in front of the 12.4-magnitude star UCAC4 248-108672, located in the constellation Scorpius, on 3 June 2013.〔 With the aid of thirteen telescopes located in Argentina, Brazil, Chile, and Uruguay,〔 a team of astronomers led by Felipe Braga Ribas, a post-doctoral astronomer of the National Observatory (ON), in Rio de Janeiro,〔 and 65 other researchers from 34 institutions in 12 countries,〔 was able to observe this occultation event, a phenomenon during which a star disappears behind its occulting body.〔 The 1.54-metre Danish National Telescope at La Silla Observatory, due to the much faster data acquisition rate of its 'Lucky Imager' camera (10 Hz), was the only telescope able to resolve the individual rings.〔 During this event, the observed magnitude was predicted to increase from 14.7 (star + Chariklo) to 18.5 (Chariklo alone) for at most 19.2 seconds.〔 This increase of 3.8 magnitudes is equivalent to a decrease in brightness by a factor 32.5. The primary occultation event was accompanied by four additional small decreases in the overall intensity of the light curve, which were observed seven seconds before ingress and seven seconds after egress.〔 These secondary occultations indicated that something was partially blocking the light of UCAC4 248-108672. The symmetry of the secondary occultations and multiple observations of the event in various locations helped reconstruct not only the shape and size of the object, but also the thickness, orientation, and location of the ring planes.〔 The relatively consistent ring properties inferred from several secondary occultation observations discredit alternative explanations for these features, such as cometary-like outgassing.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Rings of Chariklo」の詳細全文を読む スポンサード リンク
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