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K2-288Bb
K2-288Bb (previously designated EPIC 210693462 b) is a super-Earth or mini-Neptune exoplanet orbiting in the habitable zone of K2-288B, a low-mass M-dwarf star in a binary star system in the constellation of Taurus about 226 light-years from Earth. It was discovered by citizen scientists while analysing data from the ''Kepler'' spacecraft's K2 mission, and was announced on 7 January 2019. K2-288 is the third transiting planet system identified by the Exoplanet Explorers program, after the six planets of K2-138 and the three planets of K2-233. K2-288Bb is likely to be in the habitable zone of its host star, and thus may be capable on supporting life, though the planet's composition is unknown. Discovery K2-288 was observed by the Kepler space telescope during Campaign 4 of its extended K2 "Second Light" mission, lasting from April through September 2015. A group of astronomers looked through this data to try and find transiting exoplanets. However, because of Kepler's decre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K2-138
K2-138, also designated EPIC 245950175 or EE-1, is a large early K-type main sequence star with a system of up to 6 planets discovered by citizen scientists. Four were found in the first two days of the Exoplanet Explorers project on Zooniverse in early April 2017, while up to two more were revealed in further analysis. The system is almost 600 light years away in the constellation Aquarius, within K2 Campaign 12. Planetary system K2-138 is notable for its large number of planets, all found through the efforts of citizen scientists. They are designated K2-138b, c, d, e, f, and g in order from their host star. The first five were validated by Christiansen et al., while K2-138g was noted as being a likely candidate. However, since there were only two transits of it, K2-138g could not be validated. There is a possibility that the two transits for this candidate are from two individual long-period planets. All six planets are within the Super-Earth and Mini-Neptune categor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K2-233
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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-296f
Kepler-296f (also known by its Kepler Object of Interest designation KOI-1422.04) is a confirmed super-Earth exoplanet orbiting within the habitable zone of Kepler-296. The planet was discovered by NASA's ''Kepler'' spacecraft using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. NASA announced the discovery of the exoplanet on 26 February 2014. Confirmed exoplanet Kepler 296f is a super-Earth with a radius 1.79 times that of Earth. The planet orbits Kepler-296 once every 63.3 days. Habitability The planet is located within the habitable zone of Kepler-296, a region where liquid water could exist on the surface of the planet. See also * Habitability of red dwarf systems * List of potentially habitable exoplanets References External links NASA – Kepler Mission NASA – Kepler Discoveries – Summary Table NASA – Kepler-296fat The NASA Exoplanet Archive. NASA – Kepler-296fat The Exoplan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturn
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; however, with its larger volume, Saturn is over 95 times more massive. Saturn's interior is most likely composed of a core of iron–nickel and rock (silicon and oxygen compounds). Its core is surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and finally, a gaseous outer layer. Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere. An electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is weaker than Earth's, but which has a magnetic moment 580 times that of Earth due to Saturn's larger size. Saturn's magnetic field strength is around one-twentieth of Jupiter's. The outer atmosphere is g ... [...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] |
Astronomical Unit
The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits the Sun, from a maximum (aphelion) to a minimum (perihelion) and back again once each year. The astronomical unit was originally conceived as the average of Earth's aphelion and perihelion; however, since 2012 it has been defined as exactly (see below for several conversions). The astronomical unit is used primarily for measuring distances within the Solar System or around other stars. It is also a fundamental component in the definition of another unit of astronomical length, the parsec. History of symbol usage A variety of unit symbols and abbreviations have been in use for the astronomical unit. In a 1976 resolution, the International Astronomical Union (IAU) had used the symbol ''A'' to denote a length equal to the astronomical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circumstellar Habitable Zone
In astronomy and astrobiology, the circumstellar habitable zone (CHZ), or simply the habitable zone, is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure.J. F. Kasting, D. P. Whitmire, R. T. Reynolds, Icarus 101, 108 (1993). The bounds of the CHZ are based on Earth's position in the Solar System and the amount of radiant energy it receives from the Sun. Due to the importance of liquid water to Earth's biosphere, the nature of the CHZ and the objects within it may be instrumental in determining the scope and distribution of planets capable of supporting Earth-like extraterrestrial life and intelligence. The habitable zone is also called the Goldilocks zone, a metaphor, allusion and antonomasia of the children's fairy tale of " Goldilocks and the Three Bears", in which a little girl chooses from sets of three items, ignoring the ones that are too extreme (large or small, hot or cold, etc.), and set ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radial Velocity
The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is equivalent to the vector projection of the target-observer relative velocity onto the relative direction (geometry), relative direction connecting the two points. In astronomy, the point is usually taken to be the observer on Earth, so the radial velocity then denotes the speed with which the object moves away from the Earth (or approaches it, for a negative radial velocity). Formulation Given a differentiable vector \mathbf \in \mathbb^3 defining the instantaneous position of a target relative to an observer. Let with \mathbf \in \mathbb^3, the instantaneous velocity of the target with respect to the observer. The magnitude of the position vector \mathbf is defined as The quantity range rate is the time derivative of the magnitud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LHS 1140 B
LHS 1140 b is a massive, dense rocky planet orbiting within the conservative habitable zone of the red dwarf LHS 1140. Discovered in 2017 by the MEarth Project, LHS 1140 b is nearly 7 times the mass of Earth and over 60% larger in radius, putting it within the Super-Earth category of planets. It is one of the densest planets found, with a density almost twice that of Earth, along with a high surface gravity of about 2.41 Earth's. LHS 1140 b orbits entirely within the star's habitable zone and gets 41% the incident flux of Earth. The planet is only 40 light-years away and transits its star, making it an excellent candidate for atmospheric studies with ground-based and/or space telescopes. Host star LHS 1140 b orbits a very small red dwarf, LHS 1140. It is a mere 0.146 times the mass and 0.186 times the radius of the Sun with a spectral type of M4.5V. The temperature of LHS 1140 is 3216 K, and it has a luminosity of 0.00441 LS. It is at least 5 billion years old. For comparison, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GJ 9827
GJ 9827 is a star in the constellation of Pisces. It is a K-type main-sequence star with an apparent magnitude of 10.250. It is 97 light-years (30 parsecs) away, based on parallax. The rotation period of the star cannot be determined as in 2020, and can be either around 15 or 30 days, depending on interpretation of available data. Planetary system It has 3 transiting planets seen by the ''Kepler'' space observatory in their K2 survey. As of October 2017, it is the closest star discovered to have transiting exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...s found by either the Kepler or K2 missions. The planets (b, c, d) have radii of 1.62, 1.27, and 2.09 times that of the Earth, and periods of 1.209, 3.648, and 6.201 days (ratios 1:3:5). Because of its close dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fulton Gap
The small planet radius gap (also called the Fulton gap, photoevaporation valley, or Sub-Neptune Desert) is an observed scarcity of planets with radii between 1.5 and 2 times Earth's radius, likely due to photoevaporation-driven mass loss. A bimodality in the Kepler exoplanet population was first observed in 2013, and was noted as possibly confirming an emerging hypothesis that photoevaporation could drive atmospheric mass loss on close-in, low-mass planets. This would lead to a population of bare, rocky cores with smaller radii at small separations from their parent stars, and planets with thick hydrogen- and helium-dominated envelopes with larger radii at larger separations. The bimodality in the distribution was confirmed with higher-precision data in the California-Kepler Survey in 2017, which was shown to match the predictions of the photoevaporative mass-loss hypothesis later that year. Despite the implication of the word 'gap', the Fulton gap does not actually represent a r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seattle
Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest region of North America. The Seattle metropolitan area's population is 4.02 million, making it the 15th-largest in the United States. Its growth rate of 21.1% between 2010 and 2020 makes it one of the nation's fastest-growing large cities. Seattle is situated on an isthmus between Puget Sound (an inlet of the Pacific Ocean) and Lake Washington. It is the northernmost major city in the United States, located about south of the Canadian border. A major gateway for trade with East Asia, Seattle is the fourth-largest port in North America in terms of container handling . The Seattle area was inhabited by Native Americans for at least 4,000 years before the first permanent European settlers. Arthur A. Denny and his group of travelers, subsequ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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