Rings of Jupiter

Jupiter's ring system was the third to be discovered in the Solar System, after those of Saturn and Uranus. It was first observed on 4 March 1979 by the Voyager 1 space probe. It is composed of four main components: a thick inner torus of particles known as the "halo ring"; a relatively bright, exceptionally thin "main ring"; and two wide, thick and faint outer "gossamer rings", named after the moons of whose material they are composed: Amalthea and Thebe. The principal attributes of the known Jovian Rings are listed in the table. ==Main ring==

Appearance and structure orbiting at the edge of Jupiter's main ring, as imaged by the New Horizons spacecraft in 2007 The narrow and relatively thin main ring is the brightest part of Jupiter's ring system. Its outer edge is located at a radius of about (; = equatorial radius of Jupiter or ) and coincides with the orbit of Jupiter's smallest inner satellite, Adrastea. Thus the width of the main ring is around . The appearance of the main ring depends on the viewing geometry. the brightness of the main ring begins to decrease steeply at (just inward of the Adrastean orbit) and reaches the background level at —just outward of the Adrastean orbit. the situation is different. The outer boundary of the main ring, located at , or slightly beyond the orbit of Adrastea, is very steep. Inward of the orbit of Metis, the brightness of the ring rises much less than in forward-scattered light. The Metis notch serves as their boundary. The fine structure of the main ring was discovered in data from the Galileo orbiter and is clearly visible in back-scattered images obtained from New Horizons in February–March 2007. The early observations by Hubble Space Telescope (HST), Observed in back-scattered light the main ring appears to be razor thin, extending in the vertical direction no more than 30 km. Galileo and Cassini and Amalthea. :n(r)=A\times r^{-q} where n(r) dr is a number of particles with radii between r and r + dr and A is a normalizing parameter chosen to match the known total light flux from the ring. The parameter q is 2.0 ± 0.2 for particles with r  15 ± 0.3 μm. and Earth's Moon, 7.4 kg. The presence of two populations of particles in the main ring explains why its appearance depends on the viewing geometry. Volatile materials such as ices, for example, evaporate quickly. The lifetime of dust particles in the ring is from 100 to , and between the same large bodies and high velocity particles coming from outside the Jovian system. has been observed by Cassini in Saturns's C and D rings. {{Cite journal | last = Hedman | first = M. M. | author2 = Burns, J. A. | author3 = Evans, M. W. | author4 = Tiscareno, M. S. | author5 = Porco, C. C. | title = Saturn's curiously corrugated C Ring | journal = Science | volume = 332 | issue = 6030| pages =708–11 | date = 2011 | doi = 10.1126/science.1202238 | bibcode = 2011Sci...332..708H | pmid=21454753 ==Halo ring==

Appearance and structure The halo ring is the innermost and the vertically thickest Jovian ring. Its outer edge coincides with the inner boundary of the main ring approximately at the radius (). and HST, As Poynting–Robertson drag causes particles to slowly drift towards Jupiter, their orbital inclinations are excited while passing through it. The bloom of the main ring may be a beginning of the halo. The halo ring's inner boundary is not far from the strongest 2:1 Lorentz resonance. In this resonance the excitation is probably very significant, forcing particles to plunge into the Jovian atmosphere thus defining a sharp inner boundary. Being derived from the main ring, the halo has the same age. ==Gossamer rings==

Amalthea gossamer ring The Amalthea gossamer ring is a very faint structure with a rectangular cross section, stretching from the orbit of Amalthea at (2.54 RJ) to about (). The outer boundary of the ring is relatively steep; These may represent collisional debris generated from impacts with this satellite. The detection of the Amalthea gossamer ring from the ground, in Galileo images and the direct dust measurements have allowed the determination of the particle size distribution, which appears to follow the same power law as the dust in the main ring with q=2 ± 0.5. The same forces can explain a dip in the particle distribution and ring's brightness, which occurs between the orbits of Amalthea and Thebe. The peak in the brightness just inside of the Amalthea's orbit and, therefore, the vertical asymmetry the Amalthea gossamer ring may be due to the dust particles trapped at the leading (L4) and trailing (L5) Lagrange points of this moon. The particles may also follow horseshoe orbits between the Lagrangian points. The dust may be present at the leading and trailing Lagrange points of Thebe as well. This discovery implies that there are two particle populations in the gossamer rings: one slowly drifts in the direction of Jupiter as described above, while another remains near a source moon trapped in 1:1 resonance with it. == Himalia ring ==

In September 2006, as NASA's New Horizons mission to Pluto approached Jupiter for a gravity assist, it photographed what appeared to be a faint, previously unknown planetary ring or ring arc, parallel with and slightly inside the orbit of the irregular satellite Himalia. The amount of material in the part of the ring or arc imaged by New Horizons was at least 0.04 km3, assuming it had the same albedo as Himalia. If the ring (arc) is debris from Himalia, it must have formed quite recently, given the century-scale precession of the Himalian orbit. It is possible that the ring could be debris from the impact of a very small undiscovered moon into Himalia, suggesting that Jupiter might continue to gain and lose small moons through collisions.{{cite conference ==Exploration==

The existence of the Jovian rings was inferred from observations of the planetary radiation belts by Pioneer 11 spacecraft in 1975. In 1979 the Voyager 1 spacecraft obtained a single overexposed image of the ring system. Future missions to the Jovian system will provide additional information about the rings. == Gallery ==

File:JupiterRings.jpg|The ring system as imaged by Galileo File:PIA21644 - Jupiter's rings from the inside.jpg|The rings as observed from the inside by Juno File:JWST photo of Jupiter and rings.png|James Webb Space Telescope's photo of Jupiter and rings in infrared at 2.12 and 3.23 μm File:Jupiter Showcases Auroras, Hazes (NIRCam Widefield View) (jupiter-auroras2).jpeg|alt=Image of Jupiter showing its rings, moons amalthea and Adrastea, auroras, and atmospheric features.|James Web Telescope image of Jupiter, taken in Infrared light, reveals its faint rings, along with two moons, Amalthea and Adrastea, auroras, and features of its atmosphere. ==See also==