Eris (dwarf planet)

Dwarf planet beyond Pluto in the Solar System
This article is about the dwarf planet. For the asteroid with a similar appoint, see 433 Eros. For early uses, see Eris
Eris ( minor-planet appellation 136199 Eris ) is the most massive and second-largest known dwarf satellite in the Solar System. Eris is a trans-Neptunian object ( TNO ), has a high- eccentricity orbit, and is a extremity of the spread disk. Eris was discovered in January 2005 by a Palomar Observatory -based team led by Mike Brown, and its discovery was verified late that year. In September 2006 it was named after the Greco-Roman goddess of discord and discord. Eris is the ninth-most massive known object orbiting the Sun, and the sixteenth-most massive overall in the Solar System ( including moons ). It is besides the largest aim that has not been visited by a spacecraft. Eris has been measured at 2,326 ± 12 kilometers ( 1,445 ± 7 myocardial infarction ) in diameter. [ 11 ] Its mass is 0.28 percentage that of the Earth and 127 percentage that of gnome satellite Pluto, [ 20 ] [ 21 ] although Pluto is slightly larger by volume. [ 22 ] As Eris orbits the Sun, it completes one rotation every 25.9 hours, making its day length like to Earth ‘s. [ 23 ] however, other sources disagree on the rotation period. [ 24 ]

Reading: Eris (dwarf planet)

It has one large known moon, Dysnomia. In February 2016, its distance from the Sun was 96.3 astronomic units ( 1.441×1010 kilometer ; 8.95×109 nautical mile ), [ 16 ] approximately three times that of Pluto. With the exception of some long-period comets, until 2018 VG18 was discovered on December 17, 2018, Eris and Dysnomia were the most distant known natural objects in the Solar System. [ 16 ] Because Eris appeared to be larger than Pluto, NASA initially described it as the Solar System ‘s tenth planet. This, along with the candidate of early objects of alike size being discovered in the future, motivated the International Astronomical Union ( IAU ) to define the term planet for the first time. Under the IAU definition approved on August 24, 2006, Eris is a “ shadow satellite, ” along with objects such as Pluto, Ceres, Haumea and Makemake, [ 25 ] thereby reducing the phone number of acknowledge planets in the Solar System to eight, the same as before Pluto ‘s discovery in 1930. Observations of a leading eclipse by Eris in 2010 showed that it was very slightly smaller than Pluto, [ 26 ] [ 27 ] which was measured by New Horizons as 2,377 ± 4 kilometers ( 1,477 ± 2 nautical mile ) in July 2015. [ 28 ] [ 29 ]

discovery [edit ]

Eris was discovered by the team of Mike Brown, Chad Trujillo, and David Rabinowitz [ 2 ] on January 5, 2005, from images taken on October 21, 2003. [ 30 ] The discovery was announced on July 29, 2005, the lapp day as Makemake and two days after Haumea, [ 31 ] ascribable in part to events that would late lead to controversy about Haumea. The search team had been systematically scanning for large out Solar System bodies for respective years, and had been involved in the discovery of several early boastfully TNOs, including 50000 Quaoar, 90482 Orcus, and 90377 Sedna. [ 32 ] routine observations were taken by the team on October 21, 2003, using the 1.2 thousand Samuel Oschin Schmidt telescope at Palomar Observatory, California, but the trope of Eris was not discovered at that degree due to its very slow motion across the sky : The team ‘s automatic rifle image-searching software excluded all objects moving at less than 1.5 arcseconds per hour to reduce the count of false positives returned. [ 30 ] When Sedna was discovered in 2003, it was moving at 1.75 arcsec/h, and in light of that the team reanalyzed their old data with a lower limit on the angular motion, sorting through the previously excluded images by eye. In January 2005, the re-analysis revealed Eris ‘s slow motion against the background stars. [ 30 ] follow-up observations were then carried out to make a preliminary determination of Eris ‘s eye socket, which allowed the object ‘s distance to be estimated. [ 30 ] The team had planned to delay announcing their discoveries of the bright objects Eris and Makemake until farther observations and calculations were complete, but announced them both on July 29 when the discovery of another large TNO they had been tracking, Haumea, was controversially announced on July 27 by a different team in Spain. [ 2 ] Precovery images of Eris have been identified back to September 3, 1954. [ 3 ] More observations released in October 2005 revealed that Eris has a moon, late named Dysnomia. Observations of Dysnomia ‘s sphere permitted scientists to determine the mass of Eris, which in June 2007 they calculated to be ( 1.66±0.02 ) ×1022 kilogram, [ 20 ] 27 % ±2 % greater than Pluto ‘s .

identify [edit ]

Eris is named after the greek goddess Eris ( Greek Ἔρις ), a personification of strife and discord. [ 33 ] The diagnose was proposed by the Caltech team on September 6, 2006, and it was assigned on September 13, 2006, [ 34 ] following an unusually retentive period in which the object was known by the probationary designation 2003 UB313, which was granted automatically by the IAU under their name protocols for child planets. The mention Eris has two competing pronunciations, with a “ long ” or with a “ short ” e, analogous to the two competing pronunciations of the word era. [ 35 ] The classical music English pronunciation of the goddess is, with a long e. [ 7 ] however, Brown and his students [ 36 ] use, with disyllabic laxing and a short e. [ 6 ] The Greek and Latin oblique stem of the name is Erid-, [ 37 ] as can be seen in italian Eride and russian Эрида Erida, so the adjectival in English is Eridian. [ 8 ] [ 9 ]

Xena [edit ]

due to doubt over whether the aim would be classified as a planet or a child planet, because different terminology procedures apply to these classes of objects, [ 38 ] the decision on what to name the object had to wait until after the August 24, 2006, IAU predominate. [ 39 ] For a time the object became known to the wide public as Xena. “ Xena ” was an informal mention used internally by the discovery team, inspired by the title character of the television receiver series Xena: Warrior Princess. The discovery team had reportedly saved the dub “ Xena ” for the first soundbox they discovered that was larger than Pluto. According to Brown ,

We chose it since it started with an ten ( planet “ X ” ), it sounds fabulous … and we ‘ve been working to get more female deities out there ( e.g. Sedna ). besides, at the time, the television display was distillery on television, which shows you how long we ‘ve been searching ! [ 40 ]

Brown said in an consultation that the name procedure was stalled :

One reporter [ Ken Chang ] [ 41 ] called me up from The New York Times who happened to have been a ally of mine from college, [ and ] … asked me, “ What ‘s the name you guys proposed ? ” and I said, “ Well, I ‘m not going to tell. ” And he said, “ well, what do you guys call it when you ‘re equitable talking amongst yourselves ? ” … equally far as I remember this was the only meter I told anybody this in the weight-lift, and then it got everywhere, which I alone sorta felt bad about—I rather like the name. [ 42 ]

Choosing an official name [edit ]

animation showing the movement of Eris on the images used to discover it. Eris is indicated by the arrow. The three frames were taken over a period of three hours. According to skill writer Govert Schilling, Brown initially wanted to call the object “ Lila “, after a concept in Hindu mythology that described the cosmos as the consequence of a game played by Brahman. [ 32 ] The name was very alike to “ Lilah ”, the name of Brown ‘s neonate daughter. Brown was mindful of not making his name public before it had been formally accepted. He had done so with Sedna a year previously, and had been heavily criticized. however, no expostulation was raised to the Sedna appoint early than the rupture of protocol, and no competing names were suggested for Sedna. [ 43 ] He listed the address of his personal web page announcing the discovery as /~mbrown/planetlila and in the chaos following the controversy over the discovery of Haumea, forgot to change it. Rather than needlessly anger more of his companion astronomers, he merely said that the web page had been named for his daughter and dropped “ Lila ” from consideration. [ 32 ] Brown had besides speculated that Persephone, the wife of the deity Pluto, would be a good name for the object. [ 2 ] The name had been used several times in skill fiction, [ 44 ] and was popular with the public, having handily won a poll conducted by New Scientist magazine [ 45 ] ( “ Xena ”, despite merely being a nickname, came fourth. ) This was not possible once the object was classified as a dwarf planet, because there is already an asteroid with that appoint, 399 persephone. [ 2 ] With the dispute resolved, the discovery team proposed Eris on September 6, 2006. On September 13, 2006, this name was accepted as the official name by the IAU. [ 46 ] [ 47 ] Brown decided that, because the object had been considered a satellite for sol long, it deserved a identify from Greek or Roman mythology, like the early planets. The asteroids had taken the huge majority of Graeco-Roman names. Eris, whom Brown described as his darling goddess, had fortunately escaped inclusion. [ 42 ] “ Eris caused strife and disagree by causing quarrels among people ”, said Brown in 2006, “ and that ‘s what this one has done excessively ”. [ 48 ]

symbol [edit ]

There are two competing symbols in use by the astrological community for Eris : a Discordian symbol, ⯰ ( , U+2BF0 ), and a symbol like that of Mars, but with the arrow pointing down : ⯱ ( , U+2BF1 ). The erstwhile has appeared in publications by NASA. [ 49 ] Some polish astrologers have identified Eris with the hypothetical trans-Plutonian planet Proserpina ( Persephone ), which had been a staple of 20th-century science fabrication, and so use Proserpina ‘s astrological symbol : an invert Venus, basically a globus cruciger, ♁ ( , U+2641 ). [ 50 ]

categorization [edit ]

distribution of trans-Neptunian objects Eris is a trans-Neptunian gnome planet ( plutoid ). [ 51 ] Its orbital characteristics more specifically categorize it as a scattered-disk aim ( SDO ), or a TNO that has been “ confused ” from the Kuiper belt into more-distant and unusual orbits following gravitational interactions with Neptune as the Solar System was forming. Although its high orbital tendency is unusual among the known SDOs, theoretical models suggest that objects that were in the first place near the inner border of the Kuiper belt were scattered into orbits with higher inclinations than objects from the out knock. [ 52 ] Because Eris was initially thought to be larger than Pluto, it was described as the “ one-tenth planet “ by NASA and in media reports of its discovery. [ 53 ] In reception to the doubt over its condition, and because of ongoing argue over whether Pluto should be classified as a satellite, the IAU delegated a group of astronomers to develop a sufficiently accurate definition of the term planet to decide the write out. This was announced as the IAU ‘s Definition of a Planet in the Solar System, adopted on August 24, 2006. At this time, both Eris and Pluto were classified as dwarf planets, a class discrete from the new definition of planet. [ 54 ] Brown has since stated his blessing of this categorization. [ 55 ] The IAU subsequently added Eris to its Minor Planet Catalogue, designating it (136199) Eris. [ 39 ]

orb [edit ]

The eye socket of Eris ( amobarbital sodium ) compared to those of Saturn Uranus, Neptune, and Pluto ( white/gray ). The arch below the ecliptic are plotted in blue colors, and the loss dot is the Sun. The diagram on the left is a arctic view whereas the diagrams on the right are different views from the ecliptic . see from Earth, Eris makes humble loops in the sky through the configuration of Cetus Eris has an orbital menstruation of 559 years. [ 16 ] Its maximum possible distance from the Sun ( aphelion ) is 97.5 AU, and its nearest ( perihelion ) is 38 AU. [ 16 ] As the time of perihelion is defined at the epoch chosen using an unflurried two-body solution, the foster the epoch is from the date of perihelion, the less accurate the solution. numeral consolidation is required to predict the time of perihelion accurately. numeral consolidation by JPL Horizons shows that Eris came to perihelion around 1699, [ 10 ] to aphelion around 1977, [ 10 ] and will return to perihelion around December 2257. [ 10 ] Unlike the eight planets, whose orbits all lie roughly in the same plane as the Earth ‘s, Eris ‘s orb is highly disposed : it is tilted at an slant of about 44 degrees to the ecliptic. [ 3 ] When discovered, Eris and its moon were the most distant know objects in the Solar System, apart from long-period comets and outer space probes. [ 2 ] [ 56 ] It retained this distinction until the discovery of 2018 VG18 in 2018. [ 57 ] As of 2008, there were approximately forty known TNOs, most notably 2006 SQ372, 2000 OO67 and Sedna, that are presently closer to the Sun than Eris, even although their semimajor axis is larger than that of Eris ( 67.8 AU ). [ 4 ]
The distances of Eris and Pluto from the Sun in the following 1,000 years Eris ‘s orbit is highly bizarre, and brings Eris to within 37.9 AU of the Sun, a typical perihelion for confused objects. [ 58 ] This is within the orbit of Pluto, but still dependable from direct interaction with Neptune ( ~37 AU ). [ 59 ] Pluto, on the other hand, like other plutinos, follows a less tend and less character sphere and, protected by orbital plangency, can cross Neptune ‘s eye socket. [ 60 ] In about 800 years, Eris will be closer to the Sun than Pluto for some time ( see the graph at the entrust ). As of 2007, Eris has an apparent magnitude of 18.7, making it bright enough to be detectable to some amateur telescopes. [ 61 ] A 200-millimeter ( 7.9 in ) telescope with a CCD can detect Eris under golden conditions. [ vitamin d ] The reason it had not been noticed until now is its exorbitant orbital inclination ; searches for large outer Solar System objects tend to concentrate on the ecliptic plane, where most bodies are found. [ 62 ] Because of the high inclination of its orbit, Eris passes through only a few constellations of the traditional Zodiac ; it is now in the constellation Cetus. It was in Sculptor from 1876 until 1929 and Phoenix from roughly 1840 until 1875. In 2036 it will enter Pisces and stay there until 2065, when it will enter Aries. [ 10 ] It will then move into the northerly sky, entering Perseus in 2128 and Camelopardalis ( where it will reach its northernmost declination ) in 2173 .

Size, bulk and concentration [edit ]

exemplification of the leading eclipse by Eris in November 2010. The resulting eclipse chords project a round silhouette for Eris, giving a ball-shaped diameter of 2,326 km ( 1,445 michigan ) .
Size estimates

Year
Radius
Source

2005

1,199 km[63]
Hubble

2007

1,300 km[64]
Spitzer

2011

1,163 km[11]
Occultation
Mass of Eris compared[e]

The mass of Eris compared to other dwarf planets (Pluto, Haumea, Makemake, Gonggong, Quaoar, Orcus, Ceres) and Charon. The unit of mass is ×10

surface and atmosphere [edit ]

The infrared spectrum of Eris, compared to that of Pluto, shows the marked similarities between the two bodies. Arrows denote methane absorption lines. The discovery team followed up their initial identification of Eris with spectroscopic observations made at the 8 meter Gemini North Telescope in Hawaii on January 25, 2005. Infrared light from the object revealed the presence of methane ice, indicating that the come on may be similar to that of Pluto, which at the meter was the only TNO known to have coat methane, and of Neptune ‘s lunar month Triton, which besides has methane on its surface. [ 68 ] due to Eris ‘s aloof bizarre eye socket, its surface temperature is estimated to vary between about 30 and 56 K ( −243.2 and −217.2 °C ). [ 2 ] Unlike the slightly red Pluto and Triton, Eris appears about egg white. [ 2 ] Pluto ‘s red color is thought to be due to deposits of tholins on its surface, and where these deposits darken the come on, the lower albedo leads to higher temperatures and the vaporization of methane deposits. In contrast, Eris is far enough from the Sun that methane can condense onto its surface even where the albedo is moo. The condensing of methane uniformly over the coat reduces any albedo contrasts and would cover up any deposits of bolshevik tholins. [ 30 ] even though Eris can be improving to three times farther from the Sun than Pluto, it approaches near enough that some of the ices on the surface might warm enough to sublime. Because methane is highly volatile, its presence shows either that Eris has constantly resided in the distant reaches of the Solar System, where it is cold enough for methane ice to persist, or that the celestial body has an internal beginning of methane to replenish gas that escapes from its atmosphere. This contrasts with observations of another discovered TNO, Haumea, which reveal the presence of water ice rink but not methane. [ 69 ]

satellite [edit ]

[70] Artist ‘s depression of the dwarf planet Eris and its moon Dysnomia. This artistic representation is based on observations made at ESO ‘s La Silla Observatory. In 2005, the adaptive optics team at the Keck telescopes in Hawaii carried out observations of the four brightest TNOs ( Pluto, Makemake, Haumea, and Eris ), using the newly commissioned laser guide star adaptive optics system. [ 71 ] Images taken on September 10 revealed a moon in sphere around Eris. In keeping with the “ Xena ” nickname already in practice for Eris, Brown ‘s team nicknamed the moon “ Gabrielle “, after the television warrior princess ‘s buddy. When Eris received its official name from the IAU, the moon received the name Dysnomia, after the greek goddess of lawlessness who was Eris ‘s daughter. Brown says he picked it for similarity to his wife ‘s name, Diane. The name besides retains an external oblique muscle reference book to Eris ‘s old informal name Xena, portrayed on television by Lucy Lawless. [ 72 ]

Eris System

Name

Diameter (km)

Semi-major axis
( kilometer )

Mass
( 1022 kilogram )

Discovery date

Eris

2326[23]

1.6466[13]

October 21, 2003[23]

Dysnomia

700 ± 115[73]

37 273 ± 64[13]

Unknown

September 10, 2005[71]

exploration [edit ]

In the 2010s, on the heels of New Horizons ‘s successful Pluto flyby, there were multiple studies for follow-on missions to explore the Kuiper belt, among which Eris was evaluated as a campaigner. [ 74 ] It was calculated that a flyby mission to Eris would take 24.66 years using a Jupiter graveness assist, based on launch dates of April 3, 2032, or April 7, 2044. Eris would be 92.03 or 90.19 AU from the Sun when the spacecraft arrives. [ 75 ]

See besides [edit ]

Notes [edit ]

a b Calculated from the mean radius
a b Calculated based on the known parameters
^D) and albedo (p) using $H=-5\log {D{\sqrt {p}} \over 1329}$ [17] Calculated from the listed diameter ( ) and albedo ( ) using
^ For an exemplar of an amateur visualize of Eris, see Fred Bruenjes ‘ Astronomy Archived November 2, 2005, at the Wayback car
^
Mass of Eris compared (cont.)

The mass of Eris compared to the icy moons Titania (Uranus III), Oberon (Uranus IV), Rhea (Saturn V), Iapetus (Saturn VIII) and Triton (Neptune I). The unit of mass is ×10

21 kg.
A comparison to the most comparable moons of the Solar arrangement is at right .
^ Calculated by dividing the listed mass by the number book

References [edit ]

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