(136199) Éris - SpeedyLook encyclopedia

Denomination

Éris is named according to the Greek goddess Éris of the discord. Before the acceptance of this name, Éris had a provisional Désignation, 2003 UB₃₁₃ .

The designation of the asteroids and small bodies implies to give to the bodies whose orbit is known with certainty a final number. Éris has number 136199; its official scientific designation supplements is thus (136199) Éris , or possibly 136199 Éris .

Physical characteristics

Mass and dimensions

The Diamètre of Éris was evaluated to 2400 km using images taken by the Space telescope Hubble what is measurable by Hubble thanks to sophisticated techniques of image processing. According to Hubble, Éris is only 4% larger than Pluton, with a diameter of 2397 ± 100 km (Pluto measures 2306 km in diameter). Its albedo would be of: 0.86, which would be of it the object more the brilliance of the solar system after Encelade, the satellite of Saturn. Its high albedo could be caused by its frozen surface, réalimentée by the fluctuations of temperature whereas the eccentric orbit of Éris more or less brings it far from Soleil^,.

In 2007, a series of observations of the largest transneptuniens by the Space telescope Spitzer gave to Éris a diameter equal to 2600 (+400 -200) km^,.

However, unlike Pluto and Triton, Éris seems to be of gray color.

Because of its orbit, the temperature of surface of Éris varies between 30 and 56K (−243 and −217 °C).

Orbits

The Orbite of Éris is strongly eccentric and brings it to 37.78 UA of the Sun to its Périhélie and 97.56 UA with its Aphélie. It is also very tilted compared to the ecliptic (approximately 45°); its orbital period is of 556.7 A.

Éris is currently located at 97 UA of the Sun, almost at its aphelion and, put besides some Comet S at long period, is the most distant object which one knows in the solar system. Its Equatorial radius being of 67.669 UA, one knows in 2007 forty transneptuniens objects which are currently closer to the Sun than Éris but have an equatorial larger radius, like Sedna, 2000 OO₆₇, 2000 CR₁₀₅ or 1996 TL₆₆. Éris should reach its next perihelion on March 29th, 2257.

The perihelion of Éris, at approximately 37.8 UA, puts it safe from the influence of Neptune (located at 30 UA of the Sun). By comparison, Pluto and the others Plutino S follows an orbit less eccentric and tilted and related to Neptune by orbital Résonance. Because of this orbit, Éris is probably a scattered Objet. These objects would have been formed in the Ceinture of Kuiper and are scattered by Neptune whereas the solar system was formed. Although its strong slope is atypical among the known scattered objects, the models sugg-rent that the objects originally located on the internal edge of the belt of Kuiper were scattered on orbits more tilted than the objects of the external belt.

Visibility

The Magnitude connects of Éris is currently of approximately 19, which makes it detectable by some Télescope S amateurs. She was not discovered before 2005 because of her strong slope: the majority of research for the large transneptuniens objects concentrate in the field of the ecliptic, where the majority of material of the solar system are located.

Éris is currently in the constellation of the Baleine. It was in the Sculpteur of 1876 to 1929 and in the Phoenix of approximately 1840 to 1875. In 2036, it will enter the Poisson and in 2065 the Bélier. After this date, it will pass in the northern celestial hemisphere: in 2128 in Persée and 2173 in the Giraffe where it will reach its maximum variation northern. Because of its slope, Éris crosses only some constellations of the Zodiaque.

Satellite

Éris has at least a Natural satellite, named Dysnomie (officially, (136199) Éris I Dysnomie), discovered the September 10th 2005 at the Observatory of Keck in California and announced the October 2nd 2005.

This satellite is 60 times less luminous than Éris and its diameter is estimated at less than 150 km. Its orbital period is estimated at 15.774 ± 0.002 [[Day D]], Orcus or Sedna. It is only in January 2005 that Éris was really discovered, when photographs of the same patch of sky revealed its displacement. Several later observations made it possible to start to determine its orbit, its distance and its size. The team did not intend to reveal her discovery before other observations are carried out, in order to specify the size and the mass of the object; the advertisement of discovered of another object that it followed, 2003 EL₆₁, by a Spanish team, forced it to precipitate the advertisement. The name was allotted on September 13rd, 2006 following one period unusually long during which she was known by her provisional Désignation 2003 UB₃₁₃, which was automatically given by the international astronomical Union according to the protocol of designation of the minor objects.

Before this final designation, two nicknames were used for the object in the media.

“Xena” was the abstract name used by the team having discovered it. It came from heroin éponyme of the televised series Xena, warlike the . The team had preserved at drawing this nickname for the first discovered object larger than Pluton. According to Brown, it was chooses because it begin with X (for the Planet X), it sounded in a mythological way and that the team had made in kind place more female divinities among the transneptuniens objects (like Sedna); moreover, the series was then diffused. The nickname “Lila” also was used, but following a misunderstanding on planetlila , left URL of the Web page of Brown relantant the découverte^,. In answer to an uncertainty concerning its statute, and because of the debate on that of Planet of Pluto, the international astronomical Union charged a group with astronomers with defining the term of planet. This definition was adopted on August 24th, 2006; Eris was indicated “dwarf Planet” (and Pluto downgraded with the same row). The decision was strongly discussed; Mike Brown, the discoverer of Éris, has since approval this term. The UAI placed thereafter Éris in the Minor Planet Catalog , giving him designation (136199) Éris

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