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K2-229
K2-229 (also designated EPIC 228801451 or TYC 4947-834-1) is a K-type main sequence star approximately 103 parsecs (335 light years) away in the constellation Virgo. It was observed by the Kepler Space Telescope during its K2 "Second Light" mission in Campaign 10. Planetary system As of March 27, 2018, K2-229 has a system of three confirmed exoplanets. All three known planets transit their star and would orbit inside that of Mercury if placed in the Solar System. Only the innermost has a well determined mass and composition. ; K2-229b K2-229b is a Super-Earth with an iron-rich composition. It is about 17% larger than Earth by radius, but is almost 2.6 times more massive. Its high density indicates it has a core-mass fraction of about 68%, nearly identical to that of Mercury. It is believed that like Mercury, the huge core of K2-229 is the result of a giant impact event. However, unlike Mercury, it orbits extremely close to its host star, with one orbit taking a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K2-229b
K2-229b (previously designated EPIC 228801451.01) is an extremely hot, solid, iron-rich exoplanet in a close orbit around the active K-dwarf K2-229 in the constellation Virgo, 335 light years away from Earth. Characteristics Mass, radius, and temperature K2-229b is a relatively Earth-sized planet, first identified using the transit method, where a planet passes in front of its host star and blocks a tiny fraction of its light. When the planet was first discovered, only its radius was known. It was determined to be 1.165 , or about 16.5% larger than Earth. A planet of this size is most likely rocky with a solid surface, like Earth itself. However, radial velocity measurements using the HARPS spectrograph revealed that K2-229b was far denser and more massive than initially expected. The planet has a mass of 2.59 and an extremely high density of about 8.9 g/cm3, giving it about 91% more surface gravity than Earth. The unusually high mass and density of K2-229b indicates a Mercur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virgo (constellation)
Virgo is one of the constellations of the zodiac. Its name is Latin for maiden, and its old astronomical symbol is (♍︎). Lying between Leo (constellation), Leo to the west and Libra (constellation), Libra to the east, it is the second-largest constellation in the sky (after Hydra (constellation), Hydra) and the largest constellation in the zodiac. The ecliptic intersects the celestial equator within this constellation and Pisces (constellation), Pisces. Underlying these technical two definitions, the sun passes directly overhead of the equator, within this constellation, at the September equinox. Virgo can be easily found through its brightest star, Spica. Location Virgo is prominent in the spring sky in the Northern Hemisphere, visible all night in March and April. As the largest zodiac constellation, the Sun takes 44 days to pass through it, longer than any other. From 1990 and until 2062, this will take place from September 16 to October 30. It is located in the third ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More solar e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2MASS Objects
Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementary particles, theoretically with the same amount of matter, have nonetheless different masses. Mass in modern physics has multiple definitions which are conceptually distinct, but physically equivalent. Mass can be experimentally defined as a measure of the body's inertia, meaning the resistance to acceleration (change of velocity) when a net force is applied. The object's mass also determines the strength of its gravitational attraction to other bodies. The SI base unit of mass is the kilogram (kg). In physics, mass is not the same as weight, even though mass is often determined by measuring the object's weight using a spring scale, rather than balance scale comparing it directly with known masses. An object on the Moon would weigh less t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K-type Main-sequence Stars , an unusual kind of asteroid
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K-type may refer to: *AEC K-type, a bus chassis *K-type star, a stellar spectral classification *K-type filter, a type of electronic filter *K-type asteroid K-type asteroids are relatively uncommon asteroids with a moderately reddish spectrum shortwards of 0.75 μm, and a slight bluish trend longwards of this. They have a low albedo. Their spectrum resembles that of CV and CO meteorites. A larger K t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WASP-47
WASP-47 is a star similar in size and brightness to the Sun about 870 light-years away in the constellation Aquarius. It lies within the Kepler K2 campaign field 3. It was first noticed to have a hot Jupiter exoplanet orbiting every 4 days in 2012 by the Wide Angle Search for Planets (WASP) team. While it was thought to be a typical hot Jupiter system, three more planets were found in 2015: an outer gas giant within the habitable zone, a hot Neptune exterior to the hot Jupiter's orbit and a super-Earth interior to the hot Jupiter's orbit. WASP-47 is the only planetary system known to have both planets near the hot Jupiter and another planet much further out. Nomenclature and history Prior to the discovery of its planets, WASP-47 was given the 2MASS designation of 2MASS J22044873-1201079. It was also observed by the Wide-field Infrared Survey Explorer and given the designation WISE J220448.74-120108.4. When observed by NASA's K2 mission, it was given the Ecliptic Plane Inp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K2-141b
K2-141b (also designated EPIC 246393474.01) is a massive rocky exoplanet orbiting extremely close to a K Type orange main-sequence star K2-141. The planet was first discovered by the Kepler space telescope during its K2 “Second Light” mission and later observed by the HARPS-N spectrograph. It is classified as an Ultra-short Period (USP) and is confirmed to be terrestrial in nature. Its high density implies a massive iron core taking up between 30% and 50% of the planet's total mass. Characteristics Mass and radius Like the majority of known exoplanets, K2-141b was detected using the transit method, where a planet blocks a tiny fraction of its star's light as it passed between our line of the sight and its host. This method is only able to determine the radius of the planet, not its mass. However, K2-141b was also detected by the radial velocity method using the HARPS-N spectrograph. Therefore, its mass could also be determined along with its radius. The planet is classified as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K2-229 System
K, or k, is the eleventh letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''kay'' (pronounced ), plural ''kays''. The letter K usually represents the voiceless velar plosive. History The letter K comes from the Greek letter Κ (kappa), which was taken from the Semitic kaph, the symbol for an open hand. This, in turn, was likely adapted by Semitic tribes who had lived in Egypt from the hieroglyph for "hand" representing /ḏ/ in the Egyptian word for hand, ⟨ ḏ-r-t⟩ (likely pronounced in Old Egyptian). The Semites evidently assigned it the sound value instead, because their word for hand started with that sound. K was brought into the Latin alphabet with the name ''ka'' /kaː/ to differentiate it from C, named ''ce'' (pronounced /keː/) and Q, named ''qu'' and pronounced /kuː/. In the earliest Latin inscriptions, the letters C, K and Q were all used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mini-Neptune
A Mini-Neptune (sometimes known as a gas dwarf or transitional planet) is a planet less massive than Neptune but resembling Neptune in that it has a thick hydrogen–helium atmosphere, probably with deep layers of ice, rock or liquid oceans (made of water, ammonia, a mixture of both, or heavier volatiles). A gas dwarf is a gas planet with a rocky core that has accumulated a thick envelope of hydrogen, helium, and other volatiles, having, as a result, a total radius between 1.7 and 3.9 Earth radii (). The term is used in a three-tier, metallicity-based classification regime for short-period exoplanets, which also includes the rocky, terrestrial-like planets with less than and planets greater than , namely ice giants and gas giants. Properties Theoretical studies of such planets are loosely based on knowledge about Uranus and Neptune. Without a thick atmosphere, it would be classified as an ocean planet instead. An estimated dividing line between a rocky planet and a gaseous pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Planet
] An iron planet is a type of planet that consists primarily of an iron-rich core with little or no mantle. Mercury is the largest celestial body of this type in the Solar System (as the other terrestrial planets are silicate planets), but larger iron-rich exoplanets may exist. Iron is the sixth most abundant element in the universe by mass after hydrogen, helium, oxygen, carbon, and neon. Origin Iron-rich planets may be the remnants of normal metal/silicate rocky planets whose rocky mantles were stripped away by giant impacts. Some are thought to consist of diamond fields. Current planet formation models predict iron-rich planets will form in close-in orbits or orbiting massive stars where the protoplanetary disk presumably consists of iron-rich material."Characteristics of Terrestrial Planets" by John Chambers, from "The Great Planet Debate: Science as Process", August 14–16, 2008, The Johns Hopkins University Applied Physics Laboratory Kossiakoff Center, Laurel, MD. ht ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Main Sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or dwarf stars. These are the most numerous true stars in the universe and include the Sun. After condensation and ignition of a star, it generates thermal energy in its dense core region through nuclear fusion of hydrogen into helium. During this stage of the star's lifetime, it is located on the main sequence at a position determined primarily by its mass but also based on its chemical composition and age. The cores of main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Super-Earth
A super-Earth is an extrasolar planet with a mass higher than Earth's, but substantially below those of the Solar System's ice giants, Uranus and Neptune, which are 14.5 and 17 times Earth's, respectively. The term "super-Earth" refers only to the mass of the planet, and so does not imply anything about the surface conditions or habitability. The alternative term "gas dwarfs" may be more accurate for those at the higher end of the mass scale, although "mini-Neptunes" is a more common term. Definition In general, super-Earths are defined by their masses, and the term does not imply temperatures, compositions, orbital properties, habitability, or environments. While sources generally agree on an upper bound of 10 Earth masses (~69% of the mass of Uranus, which is the Solar System's giant planet with the least mass), the lower bound varies from 1 or 1.9 to 5, with various other definitions appearing in the popular media. The term "super-Earth" is also used by astronomers to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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