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216 Kleopatra () is a main-belt asteroid. It was discovered by Johann Palisa on April 10, 1880, from Pula. It is named after Cleopatra, the famous queen of Ancient Egypt. It is notable for its peculiar bilobate shape, which has been compared to a dog's bone. It was recently discovered to be a ternary asteroid, having two small moons. Physical properties and moons Kleopatra is a relatively large asteroid, measuring 217 × 94 × 81 km. Calculations from its radar albedo and the orbits of its moons show it to be a rubble pile, a loose amalgam of metal, rock, and 30 50% empty space by volume, likely due to a disruptive impact prior to the impact that created its moons. Kleopatra has an unusual shape that has been compared to a dog's bone. This bilobate shape was revealed by adaptive optics on the ESO 3.6 m Telescope at La Silla, run by the European Southern Observatory. By bouncing radar signals off the asteroid, a team of astronomers at the Arecibo radio telescope in Puerto Rico were able to develop a more detailed computer model of its shape, which confirmed the earlier results. In September 2008, Franck Marchis and his collaborators announced that by using the Keck Observatory's adaptive optics system, they had discovered two moons orbiting Kleopatra.[1] The outer and inner satellites are about 5 km and 3 km in diameter, respectively.[2]
In February 2011 they were named Alexhelios (, outer) and Cleoselene (, inner), after Cleopatra's children Alexander Helios and Cleopatra Selene II.[3] It is believed that Kleopatra's shape, rotation, and moons are due to an oblique impact perhaps 100 million years ago. The increased rotation would have elongated the asteroid and caused Alexhelios to split off. Cleoselene may have split off later, around 10 million years ago. Kleopatra is a contact binary - if it were spinning much faster, the two lobes would separate from each other, making a true binary system.[4] References External links ast:216 Kleopatra br:216 Kleopatra cy:216 Kleopatra de:(216) Kleopatra el:216 es:(216) Cleopatra eo:216 Kleopatro eu:216 Kleopatra fa: fr:(216) Cl op tre hr:216 Kleopatra id:216 Kleopatra it:216 Kleopatra la:216 Kleopatra lb:(216) Kleopatra hu:216 Kleopatra ja: ( ) no:216 Kleopatra nn:216 Kleopatra pl:216 Kleopatra pt:216 Cle patra ru:(216) simple:216 Kleopatra sk:216 Kleopatra sl:216 Kleopatra sr:216 fi:216 Kleopatra sv:216 Kleopatra tl:216 Kleopatra th:216 uk:216 vi:216 Kleopatra yo:216 Kleopatra zh:
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