E R I S

 Characteristics

              2003 UB₃₁₃ (baptized of way nonofficial as Xena) and after the meet of IAU in Setember 14th, announced for this dwarf planet the name of Eris. Are a dwarf planet plutonian transneptuniano that the discoverers describe like greater than the Pluto planet. This object has been called the tenth planet of the Solar System by its discoverers of the NASA and mass media, but his estatus official as planet remains without clarifying by the Astronomical Union the International until in August of 2006 in the international meeting of the IAU dwarf planet ofour Solar System was adopted to 200U'B ₃₁₃ like 4º.

            Recent measures show that 2003 UB₃₁₃ have an approximated size of 2,400 km being the sixteenth body of greater size of the Solar System, something greater than Pluto. To his around it turns a small natural satellite S/2005 (2003 UB₃₁₃), designated of way nonofficial like Gabrielle.

                Eris are one of the bodies that more reflected radiation in all the Solar System, which could be explained by the frozen methane that covers its surface.

            The object is at the moment to a distance of 97 astronomical units and tour around the Sun in an orbit very inclined and eccentric every 557 years. It is classified like a SDO (Scattered disk objects). And in addition to plutoniano celestial body by its characteristics of inclination and orbital  period.

            Eris were discovered by the team of Michael Brown, Chad Trujillo, and David Rabinowitz the 8 of January of the 2005 from images taken the 21 from October of the 2003. The discovery was announced the 29 of July of the 2005, the same day that other two great objects of the belt of Kuiper: 2003₆₁ and 2005 FY₉.

            The investigating equipment has been looking for objects of the outer Solar System systematically during several years and or been had related to the discovery of other great transneptúnicos objects, including a (50000) Quaoar and (90377) Sedna, therefore, we would speak of the more plutonianos bodies or dwarf planets if they have spherical form.

            Routine observations had been taken by the equipment the October 31st, 2003 using the telescope from 48 inches Samuel Hard-twisted Oschin de Monte in California. But the object was not discovered until January of the 2005, when more images of the same zone showed their slow evolution on the star bottom. Subsequent observations allowed to determine the orbit, that they as well gave to an estimation of the distance and the size.

            The equipment had glided to postpone the announcement until more observations became than they allowed determinations more guessed right of the size and mass of the body, but apparently would have been forced to advance the announcement when knowing that the rumor of the discovery would have spread and could more be announced by somebody.

            Initially it was catalogued like Eris, according to the conventions of nomenclature of astronomy for asteroids. Due to the importance of the object, it is probable that it receives an official name soon, although was baptized unofficially like Xena by his discoverers, and Lila by a page of Internet, in which this object was announced by the name of a daughter new born of one of the discoverers. In any case one is not still the definitive name, and the scientific community this suggesting if it is catalogued to 2003 UB₃₁₃ as dwarf planet is put him a name pertaining to the pantheon of the Roman Gods, to be able to follow the tradition astronomical. So that the name becomes official will have to be approved by the Astronomical Union the International which wishes that the astronomical tradition of names of the Roman Gods for planets stays. In our case, the IAU named this dwarf planet like Eris is a the Greek goddess of discord and strife. She stirs up jealousy and envy to cause fighting and anger among men. At the wedding of Peleus and Thetis, the parents of the Greek hero Achilles, all the gods with the exception of Eris were invited, and, enraged at her exclusion, she spitefully caused a quarrel among the goddesses that led to the Trojan war.

E r i s 4º dwarf planet of the Solar System

            Eris have an orbital period of about 560 years and at the moment it is almost to the Maxima distances possible of the Sun (aphelion), to 97 astronomical Earth units (14,400 million kilometers). Just as Pluto, its orbit is very eccentric and arrives at a 35 AU of the Sun during the perihelion (the distance of Pluto to the Sun varies between 29 and 49,5 AU, whereas Neptune orbits to a 30 AU). On the contrary which the telluric planets and the gas giants, whose orbits they are approximately in the same plane that the one of the Earth, the orbit of 2003 UB₃₁₃ is inclined 44° with respect to the ecliptic.

            The new object is the enough brilliant, with an apparent magnitude of 19, to be seen with a relatively modest telescope. The inclination of its orbit is responsible for which it has not been discovered until now, since most of the searches of great objects in the moved away areas more of the Solar System they are concentrated in the plane of the ecliptic in which it is most of the matter of the System.

            The brightness of an object of the Solar System depends as much on its size as of the amount of light that reflects (its Albedo). If the distance to an object and its Albedo is known, the radius from its apparent magnitude can be calculated easily. At the moment the Albedo of 2003 UB₃₁₃ is not known.

            Although from his discovery one suspected that he could be a body greater than Pluto has not been until beginnings of the 2006 that could be determined their diameter of precise form. The size of this object measured by its emission in radio waveses was calculated in approximately 3,100 km, but according to observations of the space telescope Hubble, the diameter of Xena is considered slightly in 2.398 km (± 96 km) being greater than Pluto, than it registers 2,302 km Because it could not be detected by the space telescope Spitzer must be an object with a relatively high Albedo, making it more similarity to Pluto than any other discovered object to date and therefore, plutonian.
 

            The equipment discoverer continued the study after the identification of 2003 UB₃₁₃ through spectroscopic methods made in the telescope Gemini North in Hawaii. The infrared light of the object revealed frozen methane presence, which indicates that the surface of 2003 UB₃₁₃ is enough similar to the one of Pluto.

             He is one of the three only objects of the Belt of Kuiper that has revealed the methane presence, to part of Pluto and Charon, his moon. The moon of Neptune, Triton, this related to the Belt of Kuiper with all probability and also presents/displays methane in the surface. The methane is very volatile and its presence in Eris sample that always has been in the outer end of the Solar System in which it makes sufficient cold to conserve the frozen methane.

Dwarf candidates to planets or asteroids

                    In the page Web you can obtain more data of each one of our planets and the dwarf planets defined by the IAU of our Solar System.

 

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Masm © Last update 2006-10-11)