Dwarf Planet Eris is 'Almost Perfect' Pluto Twin | Dwarf Planets & Solar System | Pluto, Eris & Planet Definition. Though the dwarf planet Eris on the edge of the solar system is much denser than Pluto, the two frigid worlds are nearly exactly the same size, a new study finds. Astronomers accurately measured Eris' diameter for the first time using observations made late last year, when they caught the dwarf planet as it passed in front of a dim star. The observations, made using several telescopes in Chile, revealed that Eris and Pluto are pretty much identical in size, making them "almost perfect" twins, researchers said. The discovery, announced today (Oct. 26) in the journal Nature, runs counter to scientists' original expectations. When Eris was first discovered in 2005, it was thought to be significantly larger than Pluto. In fact, Eris' discovery was a big reason astronomers demoted Pluto to dwarf planet status in 2006.
The new observations should help astronomers learn more about Eris' composition and evolutionary history. Watching Eris Eris details revealed. Dwarf Planet Eris is 'Almost Perfect' Pluto Twin | Dwarf Planets & Solar System | Pluto, Eris & Planet Definition. Dwarf planet Eris is Pluto's equal. An artist's depiction of Eris and its moon Dysnomia. A new study shows the distant object, residing in the Kuiper Belt, is a near-duplicate of Pluto in terms of size. Credit: NAS Moon rise over the 50-cm Caisey Harlingten telescope at San Pedro de Atacama, Chile, where one of the Eris occultation light curves was obtained. Credit: A. Maury LONDON: The dwarf planet Eris has been revealed as Pluto’s twin, with an atmosphere that periodically collapses to generate one of the brightest bodies in the Solar System. The new findings show that Eris, previously thought to be the largest body in the Solar System beyond Neptune’s orbit, is in fact a similar size to Pluto.
The observations of a rare event, in which the distant Eris passed in front of a star, also enabled the scientists to characterise the structure of the dwarf planet, indicating that the atmosphere of large, icy objects in this region of space may collapse and then reappear throughout orbit with changing proximity to the Sun. Eris_and_dysnomia_485. New Planet. Tirred up a great deal of trouble among the international astronomical community when the question of its proper designation led to a raucous meeting of the IAU in Prague. At the end of the conference, IAU members voted to demote Pluto and Eris to dwarf-planet status, leaving the solar system with only eight planets. The satellite of Eris has received the offical name Dysnomia, who in Greek mythology is Eris' daughter and the demon spirit of lawlessness. As Dysnomia is a bit of a mouthful, we tend to simply call the satellite Dy, for short.
As promised for the past year, the name Xena (and satellite Gabrielle) were simply placeholders while awaiting the IAU's decision on how an official name was to be proposed. As that process dragged on, however, many people got to know Xena and Gabrielle as the real names of these objects and are sad to see them change. Artists concept of the view from Eris with Dysnomia in the background, looking back towards the distant sun. What is it? Where is it? Faraway Eris is Pluto's twin. Astronomers have accurately measured the diameter of the faraway dwarf planet Eris for the first time by catching it as it passed in front of a faint star. This event was seen at the end of 2010 by telescopes in Chile, including the Belgian TRAPPIST telescope at ESO's La Silla Observatory. The observations show that Eris is an almost perfect twin of Pluto in size. Eris appears to have a very reflective surface, suggesting that it is uniformly covered in a thin layer of ice, probably a frozen atmosphere.
The results will be published in the 27 October 2011 issue of the journal Nature. In November 2010, the distant dwarf planet Eris passed in front of a faint background star, an event called an occultation. These occurrences are very rare and difficult to observe as the dwarf planet is very distant and small. The candidate star for the occultation was identified by studying pictures from the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory.
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