Ring system
[1][2][3] Evidence suggests that ring systems may also be found around other types of astronomical objects, including moons and brown dwarfs.
[5] Fainter planetary rings can form as a result of meteoroid impacts with moons orbiting around the planet or, in the case of Saturn's E-ring, the ejecta of cryovolcanic material.
[6][7] Ring systems may form around centaurs when they are tidally disrupted in a close encounter (within 0.4 to 0.8 times the Roche limit) with a giant planet.
Larger rocks and boulders may also be present, and in 2007 tidal effects from eight moonlets only a few hundred meters across were detected within Saturn's rings.
The maximum size of a ring particle is determined by the specific strength of the material it is made of, its density, and the tidal force at its altitude.
[18] In the time between then and 2005, observations by Voyager 2[19] and the Hubble Space Telescope[20] led to a total of 13 distinct rings being identified, most of which are opaque and only a few kilometers wide.
Evidence for this ring comes from impact craters from the Ordovician meteor event appearing to cluster in a distinctive band around the Earth's equator at that time.
The presence of this ring may have led to significant shielding of Earth from sun's rays and a severe cooling event, thus causing the Hirnantian glaciation, the coldest known period of the last 450 million years.
The rings were discovered when astronomers observed Chariklo passing in front of the star UCAC4 248-108672 on June 3, 2013 from seven locations in South America.
Because this event was observed at multiple locations, the conclusion that the dip in brightness was in fact due to rings is unanimously the leading hypothesis.
Chariklo's rings have not been officially named, but the discoverers have nicknamed them Oiapoque and Chuí, after two rivers near the northern and southern ends of Brazil.
[31] A ring around Haumea, a dwarf planet and resonant Kuiper belt member, was revealed by a stellar occultation observed on 21 January 2017.
[33] The ring plane coincides with Haumea's equator and the orbit of its larger, outer moon Hi’iaka[33] (which has a semimajor axis of ≈25,657 km).
[33] In 2023, astronomers announced the discovery of a widely separated ring around the dwarf planet and Kuiper belt object Quaoar.
[37] Such ring systems can be detected for planets observed by the transit method by additional reduction of the light of the central star if their opacity is sufficient.
[43] This substellar object, dubbed "J1407b", is most likely a free-floating brown dwarf or rogue planet several times the mass of Jupiter.
[43] J1407b's transit of V1400 Centauri revealed gaps and density variations within its disk or ring system, which has been interpreted as hints of exomoons or exoplanets forming around J1407b.
