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Kepler-20f
Kepler-20f (also known by its Kepler Object of Interest designation ''KOI-070.05'') is an exoplanet orbiting the Sun-like star Kepler-20, the second outermost of five such planets discovered by NASA's ''Kepler'' spacecraft. It is located approximately 929 light-years (285 parsecs, or about km) from Earth in the constellation Lyra. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. The planet is notable as it has the closest radius to Earth known so far. Characteristics Mass, radius and temperature Kepler-20f is very likely (>95% chance) a rocky planet because of its radius, which is notable as being the closest to Earth yet: 1.004 . However, although its radius is almost the same as Earth's, its surface conditions are not Earth-like in any way. The equilibrium temperature of Kepler-20f is approximately , too hot to support liquid water on its surface and hot enough to melt s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-20
Kepler-20 is a star 929 light-years from Earth in the constellation Lyra with a system of six known planets. The apparent magnitude of this star is 12.51, so it cannot be seen with the unaided eye. Viewing it requires a telescope with an aperture of or more. It is slightly smaller than the Sun, with 94% of the Sun's radius and about 91% of the Sun's mass. The effective temperature of the photosphere is slightly cooler than that of the Sun at , giving it the characteristic yellow hue of a stellar class G8 star. The abundance of elements other than hydrogen or helium, what astronomers term the metallicity, is approximately the same as in the Sun. It may be older than the Sun, although the margin of error here is relatively large. Planetary system On December 20, 2011, the Kepler Space Telescope team reported the discovery of a five-planet system containing three small gas giants and the first two Earth-sized extrasolar planets, Kepler-20e (the first known extrasolar plane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler Mission
The Kepler space telescope is a disused space telescope launched by NASA in 2009 to discover Earth-sized planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched into an Earth-trailing heliocentric orbit. The principal investigator was William J. Borucki. After nine and a half years of operation, the telescope's reaction control system fuel was depleted, and NASA announced its retirement on October 30, 2018. Designed to survey a portion of Earth's region of the Milky Way to discover Earth-size exoplanets in or near habitable zones and estimate how many of the billions of stars in the Milky Way have such planets, Kepler's sole scientific instrument is a photometer that continually monitored the brightness of approximately 150,000 main sequence stars in a fixed field of view. These data were transmitted to Earth, then analyzed to detect periodic dimming caused by exoplanets that cross in front of their host star. Only planets whose o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth Analog
An Earth analog, also called an Earth analogue, Earth twin, or second Earth, is a planet or moon with environmental conditions similar to those found on Earth. The term Earth-like planet is also used, but this term may refer to any terrestrial planet. The possibility is of particular interest to astrobiologists and astronomers under reasoning that the more similar a planet is to Earth, the more likely it is to be capable of sustaining complex extraterrestrial life. As such, it has long been speculated and the subject expressed in science, philosophy, science fiction and popular culture. Advocates of space colonization and space and survival have long sought an Earth analog for settlement. In the far future, humans might artificially produce an Earth analog by terraforming. Before the scientific search for and study of extrasolar planets, the possibility was argued through philosophy and science fiction. Philosophers have suggested that the size of the universe is such that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler (spacecraft)
The Kepler space telescope is a disused space telescope launched by NASA in 2009 to discover Earth-sized planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched into an Earth-trailing heliocentric orbit. The principal investigator was William J. Borucki. After nine and a half years of operation, the telescope's reaction control system fuel was depleted, and NASA announced its retirement on October 30, 2018. Designed to survey a portion of Earth's region of the Milky Way to discover Earth-size exoplanets in or near habitable zones and estimate how many of the billions of stars in the Milky Way have such planets, Kepler's sole scientific instrument is a photometer that continually monitored the brightness of approximately 150,000 main sequence stars in a fixed field of view. These data were transmitted to Earth, then analyzed to detect periodic dimming caused by exoplanets that cross in front of their host star. Only planets whose orbi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-20e
Kepler-20e is an exoplanet orbiting Kepler-20. The planet is notable as it is the first planet with a smaller radius than Earth found orbiting a Sun-like star. The planet is second-closest to the star after Kepler-20b, and at , it is far too hot to have liquid water on its surface. Along with the other four planets in the system, Kepler-20e was announced on 20 December 2011. Orbit With a semimajor axis of 0.0507 AUs, Kepler-20e's orbit has a period of 6.098 days (with an extremely small margin of error). The orbit has an inclination of 87.50°, making its transits observable from the Solar System. Like the other planets of the system, the planet has a high maximum eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-Centre (geometry), center, in geometry * Eccentricity (g ... of 0.28, but the lowest in that system. Refe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methods Of Detecting Extrasolar Planets
Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty of detecting such a faint light source, the light from the parent star causes a glare that washes it out. For those reasons, very few of the exoplanets reported have been observed directly, with even fewer being resolved from their host star. Instead, astronomers have generally had to resort to indirect methods to detect extrasolar planets. As of 2016, several different indirect methods have yielded success. Established detection methods The following methods have at least once proved successful for discovering a new planet or detecting an already discovered planet: Radial velocity A star with a planet will move in its own small orbit in response to the planet's gravity. This leads to variations in the speed with which the star move ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury (planet)
Mercury is the smallest planet in the Solar System and the closest to the Sun. Its orbit around the Sun takes 87.97 Earth days, the shortest of all the Sun's planets. It is named after the Roman god ' ( Mercury), god of commerce, messenger of the gods, and mediator between gods and mortals, corresponding to the Greek god Hermes (). Like Venus, Mercury orbits the Sun within Earth's orbit as an inferior planet, and its apparent distance from the Sun as viewed from Earth never exceeds 28°. This proximity to the Sun means the planet can only be seen near the western horizon after sunset or the eastern horizon before sunrise, usually in twilight. At this time, it may appear as a bright star-like object, but is more difficult to observe than Venus. From Earth, the planet telescopically displays the complete range of phases, similar to Venus and the Moon, which recurs over its synodic period of approximately 116 days. The synodic proximity of Mercury to Earth makes Mercury most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-20c
Kepler-20c is an exoplanet orbiting Kepler-20. It has a mass similar to Neptune but is slightly smaller. Despite being the third-closest planet to Kepler-20, it is still close to the star, meaning that it is a hot Neptune A hot Neptune or Hoptune is a type of giant planet with a mass similar to that of Uranus or Neptune orbiting close to its star, normally within less than 1 AU. The first hot Neptune to be discovered with certainty was Gliese 436 b in 2007, an exo .... Along with the other four planets in the system, Kepler-20c was announced on 20 December 2011. References Exoplanets discovered in 2011 C 20c Hot Neptunes Transiting exoplanets {{Extrasolar-planet-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-20d
Kepler-20d is an exoplanet orbiting Kepler-20. It has a mass and radius similar to Neptune. Despite being the furthest planet from the star, it has an orbit similar to Mercury, meaning that it is a Hot Neptune A hot Neptune or Hoptune is a type of giant planet with a mass similar to that of Uranus or Neptune orbiting close to its star, normally within less than 1 AU. The first hot Neptune to be discovered with certainty was Gliese 436 b in 2007, an exo .... Along with the other four planets in the system, Kepler-20d was announced on December 20, 2011. ReferencesKepler-20d , Wayback Machine Exoplanets discovered in 2011 D 20d Hot Neptunes Transiting exoplanets {{Extrasolar-planet-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naked Eye
Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collecting optical instrument, such as a telescope or microscope, or eye protection. Vision corrected to normal acuity using corrective lenses is still considered "naked". In astronomy, the naked eye may be used to observe celestial events and objects visible without equipment, such as conjunctions, passing comets, meteor showers, and the brightest asteroids, including 4 Vesta. Sky lore and various tests demonstrate an impressive variety of phenomena visible to the unaided eye. Basic properties Some basic properties of the human eye are: *Quick autofocus from distances of 25 cm (young people) to 50 cm (most people 50 years and older) to infinity. * Angular resolution: about 1 arcminute, approximately 0.017° or 0.0003 radians, which corresponds to 0.3 m at a 1 km distance. *Field of view (FOV): simultaneous visual percepti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's light caused by interstellar dust along the line of sight to the observer. The word ''magnitude'' in astronomy, unless stated otherwise, usually refers to a celestial object's apparent magnitude. The magnitude scale dates back to the ancient Roman astronomer Claudius Ptolemy, whose star catalog listed stars from 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined in a way to closely match this historical system. The scale is reverse logarithmic: the brighter an object is, the lower its magnitude number. A difference of 1.0 in magnitude corresponds to a brightness ratio of \sqrt /math>, or about 2.512. For example, a star of magnitude 2.0 is 2.512 times as bright as a star of magnitude 3.0, 6. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Arizona Press
The University of Arizona Press, a publishing house founded in 1959 as a department of the University of Arizona, is a nonprofit publisher of scholarly and regional books. As a delegate of the University of Arizona to the larger world, the Press publishes the work of scholars wherever they may be, concentrating upon scholarship that reflects the special strengths of the University of Arizona, Arizona State University, and Northern Arizona University. The Press publishes about fifty books annually and has some 1,400 books in print. These include scholarly titles in American Indian studies, anthropology, archaeology, environmental studies, geography, Chicano studies, history, Latin American studies, and the space sciences. The UA Press has award-winning books in more than 30 subject areas. The UA Press also publishes general interest books on Arizona and the Southwest borderlands. In addition, the Press publishes books of personal essays, such as Nancy Mairs's ''Plaintext'' and tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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