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K2-138b
K2-138b is a potentially rocky Super-Earth exoplanet orbiting every 2 days around a K1V star. The planet, along with the four others in the system, was found by citizen scientists of the Exoplanet Explorers project on Zooniverse. It was the final planet found in the system and was officially announced on January 8, 2018. K2-138b is the smallest planet of K2-138 with a radius of 1.57 , meaning it could be rocky. It orbits its host star every 2.35 days at a distance of 0.0338 AU. At this proximity, the planet is likely very hot and receives 486 times the stellar flux as Earth. The planet has a Mass of and a bulk density of g/cm−3, which is an earth-like density. The planet has likely a rocky core and a substantial atmospheric layer, composed of volatiles. The K2-138 system is unique for being the first exoplanet system discovered entirely by citizen scientists. The K2-138 system, including K2-138b will be studied with CHEOPS to further constrain the mass of the planets with ... [...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] |
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] |
Transit Method
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 mov ... [...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] |
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, initially detected in 1988, was confirmed in 2003. There are many methods of detecting exoplanets. Transit photometry and Doppler spectroscopy have found the most, but these methods suffer from a clear observational bias favoring the detection of planets near the star; thus, 85% of the exoplanets detected are inside the tidal locking zone. In several cases, multiple planets have been observed around a star. About 1 in 5 Sun-like starsFor the purpose of this 1 in 5 statistic, "Sun-like" means G-type star. Data for Sun-like stars was not available so this statistic is an extrapolation from data about K-type stars. have an "Earth-sized"For the purpose of this 1 in 5 statistic, Earth-sized means 1–2 Earth radii. planet in the habitable zone. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zooniverse
Zooniverse is a citizen science web portal owned and operated by the Citizen Science Alliance. It is home to some of the Internet's largest, most popular and most successful citizen science projects. The organization grew from the original Galaxy Zoo project and now hosts dozens of projects which allow volunteers to participate in crowdsourced scientific research. It has headquarters at Oxford University and the Adler Planetarium. Unlike many early internet-based citizen science projects (such as SETI@home) which used spare computer processing power to analyse data, known as volunteer computing, Zooniverse projects require the active participation of human volunteers to complete research tasks. Projects have been drawn from disciplines including astronomy, ecology, cell biology, humanities, and climate science. , the Zooniverse community consisted of more than 1 million registered volunteers. By March 2019, that number had reportedly risen to 1.6 million. The volunteers are oft ... [...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] |
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] |
CHEOPS
Khufu or Cheops was an ancient Egyptian monarch who was the second pharaoh of the Fourth Dynasty, in the first half of the Old Kingdom period (26th century BC). Khufu succeeded his father Sneferu as king. He is generally accepted as having commissioned the Great Pyramid of Giza, one of the Seven Wonders of the Ancient World, but many other aspects of his reign are poorly documented. The only completely preserved portrait of the king is a three-inch high ivory figurine found in a temple ruin of a later period at Abydos in 1903. All other reliefs and statues were found in fragments, and many buildings of Khufu are lost. Everything known about Khufu comes from inscriptions in his necropolis at Giza and later documents. For example, Khufu is the main character noted in the Westcar Papyrus from the 13th dynasty. Most documents that mention king Khufu were written by ancient Egyptian and Greek historians around 300 BC. Khufu's obituary is presented there in a conflicting wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transit-timing Variation
Transit-timing variation is a method for detecting exoplanets by observing variations in the timing of a transit. This provides an extremely sensitive method capable of detecting additional planets in the system with masses potentially as small as that of Earth. In tightly packed planetary systems, the gravitational pull of the planets among themselves causes one planet to accelerate and another planet to decelerate along its orbit. The acceleration causes the orbital period of each planet to change. Detecting this effect by measuring the change is known as transit-timing variations. "Timing variation" asks whether the transit occurs with strict periodicity or if there's a variation. The first significant detection of a non-transiting planet using transit-timing variations was carried out with NASA's Kepler telescope. The transiting planet Kepler-19b shows transit-timing variation with an amplitude of 5 minutes and a period of about 300 days, indicating the presence of a second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Exoplanets Discovered In 2017
This is a List of exoplanets discovered in 2017. For exoplanets detected only by radial velocity, the mass value is actually a lower limit. (See Minimum mass for more information) {, class="wikitable plainrowheaders sortable" style="width: 100%; font-size: 83%; text-align: center;" !Name !data-sort-type="number", Mass () !data-sort-type="number", Radius () !data-sort-type="number", Period (days) !data-sort-type="number", Semi-major axis (AU) !data-sort-type="number", Temp. ( K) !Discovery method !data-sort-type="number", Distance (ly) !data-sort-type="number", Host star mass () !data-sort-type="number", Host star temp. (K) !Remarks , - , BD+03 2562 b , 6.4 , , 481.9 , 1.3 , , style="background:#00FF00", radial vel. , 8540 , 1.14 , 4095 , , - , CoRoT-30 b , 2.90 , 1.009 , 9.06005 , 0.0844 , , style="background:#FFFF00", transit , 3100 , 0.98 , 5650 , , - , CoRoT-31 b , 0.84 , 1.46 , 4.62941 , 0.0586 , , style="background:#FFFF00", transit , 7000 , 1. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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