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NGC 6791
NGC 6791 is an open star cluster in the Lyra constellation. It was discovered by Friedrich August Theodor Winnecke in 1853. At roughly 8 billion years old, and with an iron to hydrogen abundance ratio that is more than twice that of the Sun, it is one of the oldest and most metal-rich clusters in the Milky Way. This is contrary to the typical rule-of-thumb where older means more metal-poor. Compounded with the fact that it has an unusually high population of stars, NGC 6791 is among the most studied clusters in the sky. Age studies Among the dimmest stars in the cluster are groups of white dwarfs that are 6 billion years old and another group that appear to be 4 billion years old. The ages are out of sync with those of the cluster's normal stars, which are 8 billion years old. This seeming contradiction in age for this cluster has been studied and a solution proposed with age of about 8 billion years. The Kepler Mission In March 2009 NASA launched the Kepler Mission spacecraf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 6791 Cluster
NGC commonly refers to: * New General Catalogue of Nebulae and Clusters of Stars, a catalogue of deep sky objects in astronomy NGC may also refer to: Companies * NGC Corporation, name of US electric company Dynegy, Inc. from 1995 to 1998 * National Gas Company of Trinidad and Tobago, state-owned natural gas company in Trinidad and Tobago * National Grid plc, a former name of National Grid Electricity Transmission plc, the operator of the British electricity transmission system * Northrop Grumman Corporation, aerospace and defense conglomerate formed from the merger of Northrop Corporation and Grumman Corporation in 1994 * Numismatic Guaranty Corporation, coin certification company in the United States Other uses * National Gallery of Canada, art gallery founded in 1880 in Ottawa, Canada * National Geographic (American TV channel), National Geographic, documentary and reality television channel established in the United States in 2001 formerly called National Geographic Chann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acta Astronomica
''Acta Astronomica'' is a quarterly peer-reviewed scientific journal covering astronomy and astrophysics. It was established in 1925 by the Polish astronomer Tadeusz Banachiewicz. Initially, the journal published articles in Latin, later English, French, and German were added as allowed journal languages. Nowadays, all papers are published in English. The journal is published by Copernicus Foundation for Polish Astronomy and the editors-in-chief are M. Jaroszyński and Andrzej Udalski (University of Warsaw). Abstracting and indexing This journal is indexed in Current Contents/Physical, Chemical & Earth Sciences, the Science Citation Index Expanded, and Scopus. According to the ''Journal Citation Reports'', the journal has a 2019 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a gi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Counterclockwise
Two-dimensional rotation can occur in two possible directions. Clockwise motion (abbreviated CW) proceeds in the same direction as a clock's hands: from the top to the right, then down and then to the left, and back up to the top. The opposite sense of rotation or revolution is (in Commonwealth English) anticlockwise (ACW) or (in North American English) counterclockwise (CCW). Terminology Before clocks were commonplace, the terms "sunwise" and "deasil", "deiseil" and even "deocil" from the Scottish Gaelic language and from the same root as the Latin "dexter" ("right") were used for clockwise. " Widdershins" or "withershins" (from Middle Low German "weddersinnes", "opposite course") was used for counterclockwise. The terms clockwise and counterclockwise can only be applied to a rotational motion once a side of the rotational plane is specified, from which the rotation is observed. For example, the daily rotation of the Earth is clockwise when viewed from above the South P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 6791 Map
NGC commonly refers to: * New General Catalogue of Nebulae and Clusters of Stars, a catalogue of deep sky objects in astronomy NGC may also refer to: Companies * NGC Corporation, name of US electric company Dynegy, Inc. from 1995 to 1998 * National Gas Company of Trinidad and Tobago, state-owned natural gas company in Trinidad and Tobago * National Grid plc, a former name of National Grid Electricity Transmission plc, the operator of the British electricity transmission system * Northrop Grumman Corporation, aerospace and defense conglomerate formed from the merger of Northrop Corporation and Grumman Corporation in 1994 * Numismatic Guaranty Corporation, coin certification company in the United States Other uses * National Gallery of Canada, art gallery founded in 1880 in Ottawa, Canada * National Geographic, documentary and reality television channel established in the United States in 2001 formerly called National Geographic Channel * Native Girls Code, US non-profit org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minute Of Arc
A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The nautical mile (nmi) was originally defined as the arc length of a minute of latitude on a spherical Earth, so the actual Earth circumference is very near . A minute of arc is of a radian. A second of arc, arcsecond (arcsec), or arc second, denoted by the symbol , is of an arcminute, of a degree, of a turn, and (about ) of a radian. These units originated in Babylonian astronomy as sexagesimal subdivisions of the degree; they are used in fields that involve very small angles, such as astronomy, optometry, ophthalmology, optics, navigation, land surveying, and marksmanship. To express even smaller angles, standard SI prefixes can be employed; the milliarcsecond (mas) and microarcsecond (μas), for instance, are commonly used in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-19
Kepler-19 (TYC 3134-1549-1, 2MASS J19214099+3751064, GSC 03134-01549, KOI-84) is a G7V star that is host to planets Kepler-19b, Kepler-19c, and Kepler-19d. It is located five arcminutes northwest of the much more distant open cluster NGC 6791. Planetary system There are three known planets in the Kepler-19 planetary system. Planet b was discovered by the transit method, c by transit-timing variations and d by 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 rate of change of the distance or range between the two points. It is equivalent to the vector projection ... measurements. References External links * NASA, Kepler missionTable of Confirmed Planets Lyra (constellation) G-type main-sequence stars Planetary systems with three confirmed planets Planetary transit variables 84 J19214099+3751064 {{main-star-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Light (astronomy)
In astronomy, first light is the first use of a telescope (or, in general, a new instrument) to take an astronomical image after it has been constructed. This is often not the first viewing using the telescope; optical tests will probably have been performed to adjust the components. Characteristics The first light image is normally of little scientific interest and is of poor quality, since the various telescope elements are yet to be adjusted for optimum efficiency. Despite this, a first light is always a moment of great excitement, both for the people who design and build the telescope and for the astronomical community, who may have anticipated the moment for many years while the telescope was under construction. A well-known and spectacular astronomical object is usually chosen as a subject. Historical examples The famous Hale Telescope of Palomar Observatory saw first light on 26 January 1949, targeting NGC 2261 under the direction of American astronomer Edwin Powel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Orbit
A heliocentric orbit (also called circumsolar orbit) is an orbit around the barycenter of the Solar System, which is usually located within or very near the surface of the Sun. All planets, comets, and asteroids in the Solar System, and the Sun itself are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits, as they orbit their respective planet (although the Moon has a convex orbit around the Sun). The barycenter of the Solar System, while always very near the Sun, moves through space as time passes, depending on where other large bodies in the Solar System, such as Jupiter and other large gas planets, are located at that time. A similar phenomenon allows the detection of exoplanets by way of the radial-velocity method. The ''helio-'' prefix is derived from the Greek word "ἥλιος", meaning "Sun", and also Helios, the personification of the Sun in Greek mythology. The fi ... [...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 mov ... [...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] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew spacecraft, and the planned Lunar Gateway space station. The agency is also responsible for the Launch Services Program, which provides oversight of launch operations and countdown m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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3 (three) is a number, numeral and digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious or cultural significance in many societies. Evolution of the Arabic digit The use of three lines to denote the number 3 occurred in many writing systems, including some (like Roman and Chinese numerals) that are still in use. That was also the original representation of 3 in the Brahmic (Indian) numerical notation, its earliest forms aligned vertically. However, during the Gupta Empire the sign was modified by the addition of a curve on each line. The Nāgarī script rotated the lines clockwise, so they appeared horizontally, and ended each line with a short downward stroke on the right. In cursive script, the three strokes were eventually connected to form a glyph resembling a with an additional stroke at the bottom: ३. The Indian digits spread to the Caliphate in the 9th c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
