Keplerian /kep lear"ee euhn/, adj.
/kep"leuhr/, n.
1. Johann /yoh"hahn/, 1571-1630, German astronomer.
2. a crater in the second quadrant of the face of the moon having an extensive ray system: about 22 miles (35 km) in diameter.

* * *

▪ United States satellite
      U.S. satellite, to be launched into orbit around the Sun in 2009, designed to detect extrasolar planets (extrasolar planet) by watching for a slight dimming during transits as these bodies pass in front of their stars (star). An important objective of Kepler's mission will be to determine the percentage of planets that are in or near their stars' habitable zones—that is, the distances from the stars at which liquid water, and therefore possibly life, could exist.

      Detecting the transit of an extrasolar planet is very challenging. For example, the diameter of Earth is only 1/109th that of the Sun, so that, for an outside observer of the solar system, the passage of Earth would dim the output of the Sun by only 0.008 percent. In addition, a planet's orbital plane must be aligned to pass in front of the star. Continuous observation without atmospheric distortion or day-night cycles—not possible from Earth—is essential to the mission. Kepler will be placed in a heliocentric orbit with a 372.5-day period so it gradually trails Earth, thus avoiding effects from the magnetosphere that might interfere with the mission. Launch is scheduled for April 10, 2009, with operations starting about a month later.

      The spacecraft will carry a single 95-cm (37-inch) telescope that will stare at the same patch of sky (105 square degrees) for at least four years. The selected region is in the constellation Cygnus, which is out of the plane of the solar system to avoid fogging by light scattered by interplanetary dust or reflected by asteroids (asteroid). Charge-coupled devices (CCDs) will operate as light sensors rather than as imagers in order to capture small changes in star brightness during the mission. The scene will be out of focus so that each star covers several pixels; if the stars were not defocused, pixels in the CCDs would become saturated and reduce the precision of the observations. Stars fainter than visual magnitude 14 will be rejected, but this will leave more than 100,000 stars in the field of view. For a star with an Earth-like planet, scientists estimate that the probability of Kepler's observing that planet eclipsing its star is about 0.47 percent. If Earth-like planets do exist, Kepler is likely to observe them.

Dave Dooling, Jr.

* * *

Universalium. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • KEPLER (J.) — Les sillons de l’espace où l’on navigue sans effort sont elliptiques. Qui ne le sait aujourd’hui? Mais combien celui qui les découvrit est méconnu! Il ne faut pas accuser trop vite l’ingratitude de l’histoire. Kepler écrivit la pièce maîtresse de …   Encyclopédie Universelle

  • Kepler-11 — es una estrella similar al Sol alrededor del cual orbitan seis planetas. Descubrimiento Descubridor Telescopio Espacial Kepler (Sistema plan …   Wikipedia Español

  • Kepler-7b — Comparación del tamaño de Kepler 7 b con Júpiter. Descubrimiento Fecha 2010 01 04 …   Wikipedia Español

  • Kepler-11 — Représentation du système de Kepler 11. Données d observation (Époque J2000.0) Ascension droite 19h 48m 27,62s Déclinaison …   Wikipédia en Français

  • Kepler-11 — Звезда Звезда Кеплер 11 в представлении художника во время тройного транзи …   Википедия

  • Kepler-9 b — Экзопланета Списки экзопланет …   Википедия

  • Kepler-9b — Tailles comparées de Kepler 9b et de Jupiter Étoile Nom Kepler 9 Ascension droite 19h 02m 17,76s …   Wikipédia en Français

  • Kepler-9c — Tailles comparées de Kepler 9c et de Jupiter Étoile Nom Kepler 9 Ascension droite 19h 02m 17,76s …   Wikipédia en Français

  • Kepler-9d — Étoile Nom Kepler 9 Ascension droite 19h 02m 17,76s Déclinaison +38° 24′ 3,2″ Type spectral G2V Constellation Lyre …   Wikipédia en Français

  • Kepler-19 — Звезда Сравнительные размеры Со …   Википедия

  • Kepler-10 b — Экзопланета Списки экзопланет Kepler 10b в представлении художника …   Википедия

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”