Tiny planet orbits faraway star.Taking advantage of some gravitational grav·i·ta·tion n. 1. Physics a. The natural phenomenon of attraction between physical objects with mass or energy. b. The act or process of moving under the influence of this attraction. 2. sleight of hand sleight of hand n. pl. sleights of hand 1. A trick or set of tricks performed by a juggler or magician so quickly and deftly that the manner of execution cannot be observed; legerdemain. 2. , astronomers have found indirect evidence of the smallest planet known to exist beyond our solar system solar system, the sun and the surrounding planets, natural satellites, dwarf planets, asteroids, meteoroids, and comets that are bound by its gravity. The sun is by far the most massive part of the solar system, containing almost 99.9% of the system's total mass. . Just five times as heavy as Earth, the planet circles a red dwarf red dwarf A small, dim star with relatively cool surface temperatures, positioned to the lower right on the main sequence in the Hertzsprung-Russell diagram. Red dwarfs, at about 0.1 to 0. , a low-mass star. The planet orbits three times farther from its star than Earth does from the sun. Taking into account the planet's size and orbit, researchers estimate that the planet's surface temperature is 220[degrees]C, similar to that of Pluto. Red dwarfs are the most common stars in the Milky Way Milky Way, the galaxy of which the sun and solar system are a part, seen as a broad band of light arching across the night sky from horizon to horizon; if not blocked by the horizon, it would be seen as a circle around the entire sky. . The new discovery therefore suggests that planets with masses such as Earth's may not be rare, says Kailash Sahu of the Space Telescope Science Institute The Space Telescope Science Institute (STScI) is the science operations center for the Hubble Space Telescope (HST; in orbit since 1990) and for the James Webb Space Telescope (JWST; scheduled to be launched in 2013). in Baltimore. He and his colleagues report their finding in the Jan. 26 Nature. To detect the planet, which lies about 20,000 light-years from earth astronomers relied on one of the stranger properties of gravity: It acts as a magnifying lens. When one star briefly passes in front of another, the foreground star amplifies the light of the background star. If the foreground star happens to have a planetary companion, researchers will see brightening over a longer period of time. The team found that the brightening lasted about 12 hours longer than it would have if the foreground star had had no partner. The astronomers deduced that the passing red dwarf has a small planet orbiting it. 3Researchers will have to wait for another chance alignment between stars to learn more about the planet.--R.C. |
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