A moon for Dionysus.Dionysus, the hard-partying god of wine in Greek mythology Greek mythology Oral and literary traditions of the ancient Greeks concerning their gods and heroes and the nature and history of the cosmos. The Greek myths and legends are known today primarily from Greek literature, including such classic works as Homer's Iliad and , never lacked for a companion. Dionysus, the near-Earth asteroid, also has a partner in its wanderings. Astronomers have found evidence that the rocky body formally dubbed 3671 Dionysus has a moon of its own. Although several other asteroids This is a list of numbered minor planets, nearly all of them asteroids, in sequential order. As of late September 2007 there are 164,612 numbered minor planets, and many more not yet numbered. Most asteroids are ordinary and not particularly noteworthy. are suspected of having a companion, this represents only the second confirmed case of such a phenomenon. Scientists working at the European Southern Observatory's La Silla Observatory La Silla Observatory is an astronomical observatory in Chile with eighteen telescopes. Nine of these telescopes were built by the European Southern Observatory (ESO) organisation, and several of the others are partly maintained by ESO. in La Serena, Chile La Serena ("the serene one") is the second oldest city in Chile. The city, located 471 km north of Santiago, has a population of 147,815, according to the 2002 census. There are also 12,333 inhabitants of the immediately surrounding countryside. , made the discovery while monitoring fluctuations in the amount of sunlight reflected from the surface of Dionysus. They expected to see small, periodic fluctuations associated with the asteroid's rotation and irregular shape. Stefano Mottola and Gerhard Hahn of the German Aerospace Research Establishment in Berlin were puzzled by an additional dip in reflectivity re·flec·tiv·i·ty n. pl. re·flec·tiv·i·ties 1. The quality of being reflective. 2. The ability to reflect. 3. . The discovery suggested that an unseen body had moved in front of the asteroid, eclipsing some of the reflected sunlight at precise intervals. The team successfully predicted the next time they should see such an eclipse. In addition, astronomers Petr Pravec and Lenka Sarounova of the Ondrejov Observatory near Prague recorded another eclipse of Dionysus. The European Southern Observatory European Southern Observatory (ESO), an intergovernmental organization for astronomical research with headquarters in Garching, near Munich, Germany. The ESO began in 1962 as a consortium among Belgium, Denmark, France, Germany, the Netherlands, and Sweden. announced the finding in late July, and astronomers plan to continue observations through December, when Dionysus will no longer be visible in the southern sky. Discovered in 1984, the asteroid passes relatively close to Earth once every 13 years; its most recent such approach occurred July 6. Bad weather on Earth prevented follow-up observations in August and early September. However, newly reported analyses of earlier data suggest that the moon has a diameter of about 0.5 kilometer, roughly half the size of tiny Dionysus, and that it orbits the asteroid from a distance of just a few kilometers, Hahn told Science News. In contrast, the moon known as Dactyl dactyl /dac·tyl/ (dak´til) a digit. dac·tyl n. A finger or toe; digit. dactyl a digit. , which the Galileo spacecraft discovered and photographed when it flew past asteroid 243 Ida in 1993, measures about 1.5 Ian, or only one-fortieth the diameter of Ida. |
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