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9 Boötis
9 Boötis is a single, variable star in the northern constellation of Boötes, located around 630 light years away from the Sun. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.0. This object is moving closer to the Earth with a heliocentric radial velocity of −41 km/s. This is an aging giant star with a stellar classification of K3 III, which indicates it has exhausted the hydrogen at its core and evolved of the main sequence. As a consequence, its outer atmosphere has swollen to 44 times the radius of the Sun. It is a suspected irregular variable that ranges in photographic magnitude from 6.1 down to 6.6. 9 Boötis is considered mildly lithium-rich with a moderate level of chromospheric activity. It is radiating 857 times the luminosity of the Sun from its enlarged photosphere at an effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boötes
Boötes ( ) is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from , which comes from 'herder, herdsman' or 'plowman' (literally, 'ox-driver'; from ''boûs'' 'cow'). One of the 48 constellations described by the 2nd-century astronomer Ptolemy, Boötes is now one of the 88 modern constellations. It contains the List of brightest stars, fourth-brightest star in the night sky, the orange giant Arcturus. Epsilon Boötis, or Izar, is a colourful multiple star popular with amateur astronomers. Boötes is home to many other bright stars, including eight above the fourth magnitude and an additional 21 above the fifth magnitude, making a total of 29 stars easily visible to the naked eye. History and mythology In ancient Babylon, the stars of Boötes were known as SHU.PA. They were apparently depicted as the god Enlil, who was the leader of the Babylonian religion, Babyloni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Magnitude
Photographic magnitude ( or ) is a measure of the relative brightness of a star or other astronomical object as imaged on a photographic film emulsion with a camera attached to a telescope. An object's apparent photographic magnitude depends on its intrinsic luminosity, its distance and any extinction of light by interstellar matter existing along the line of sight to the observer. Photographic observations have now been superseded by electronic photometry such as CCD charge-coupled device cameras that convert the incoming light into an electric current by the photoelectric effect. Determination of magnitude is made using a photometer. Method Prior to photographic methods to determine magnitude, the brightness of celestial objects was determined by visual photometric methods. This was simply achieved with the human eye by compared the brightness of an astronomical object with other nearby objects of known or fixed magnitude: especially regarding stars, planets and other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hipparcos Objects
''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions and distances of celestial objects on the sky. This permitted the first high-precision measurements of the luminosity, intrinsic brightnesses, proper motions, and parallaxes of stars, enabling better calculations of their distance and tangential velocity. When combined with radial velocity measurements from spectroscopy, astrophysicists were able to finally measure all six quantities needed to determine the motion of stars. The resulting ''Hipparcos Catalogue'', a high-precision catalogue of more than 118,200 stars, was published in 1997. The lower-precision ''Tycho Catalogue'' of more than a million stars was published at the same time, while the enhanced Tycho-2 Catalogue of 2.5 million stars was published in 2000. ''Hipparcos'' follow-up mission, ''Gaia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Draper Catalogue Objects
Henry may refer to: People and fictional characters * Henry (given name), including lists of people and fictional characters * Henry (surname) * Henry, a stage name of François-Louis Henry (1786–1855), French baritone Arts and entertainment * Henry (2011 film), ''Henry'' (2011 film), a Canadian short film * Henry (2015 film), ''Henry'' (2015 film), a virtual reality film * ''Henry: Portrait of a Serial Killer'', a 1986 American crime film * Henry (comics), ''Henry'' (comics), an American comic strip created in 1932 by Carl Anderson * "Henry", a song by New Riders of the Purple Sage Places Antarctica * Henry Bay, Wilkes Land Australia *Henry River (New South Wales) *Henry River (Western Australia) Canada * Henry Lake (Vancouver Island), British Columbia * Henry Lake (Halifax County), Nova Scotia * Henry Lake (District of Chester), Nova Scotia New Zealand * Lake Henry (New Zealand) * Henry River (New Zealand) United States * Henry, Illinois * Henry, Indiana * Henry, Nebras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flamsteed Objects
John Flamsteed (19 August 1646 – 31 December 1719) was an English astronomer and the first Astronomer Royal. His main achievements were the preparation of a 3,000-star catalogue, ''Catalogus Britannicus'', and a star atlas called '' Atlas Coelestis'', both published posthumously. He also made the first recorded observations of Uranus, although he mistakenly catalogued it as a star, and he laid the foundation stone for the Royal Greenwich Observatory. Life Flamsteed was born in Denby, Derbyshire, England, the only son of Stephen Flamsteed and his first wife, Mary Spadman. He was educated at the free school of Derby and at Derby School, in St Peter's Churchyard, Derby, near where his father carried on a malting business. At that time, most masters of the school were Puritans. Flamsteed had a solid knowledge of Latin, essential for reading the scientific literature of the day, and a love of history, leaving the school in May 1662.Birks, John L. (1999) ''John Flamsteed, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Durchmusterung Objects
In astronomy, Durchmusterung or Bonner Durchmusterung (BD) is an astrometric star catalogue of the whole sky, published by the Bonn Observatory in Germany from 1859 to 1863, with an extension published in Bonn in 1886. The name comes from ('run-through examination'), a German word used for a systematic survey of objects or data. The term has sometimes been used for other astronomical surveys, including not only stars, but also the search for other celestial objects. Special tasks include celestial scanning in electromagnetic spectrum, electromagnetic wavelengths shorter or longer than visible light waves. Original catalog The Bonner Durchmusterung (abbreviated BD), was initiated by Friedrich Wilhelm Argelander, Friedrich Argelander and using observations largely carried out by his assistants, which resulted in a catalogue of the positions and apparent magnitudes of 342,198 stars down to approximate apparent magnitude 9.5 and covering the sky from 90°N to 2°S declination. The cat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irregular Variables
An irregular variable is a type of variable star in which variations in brightness show no regular periodicity. There are two main sub-types of irregular variable: eruptive and pulsating. Eruptive irregular variables are divided into three categories: * Group I variables are split into subgroups IA (spectral types O to A) and IB (spectral types F through M). * Orion variables, GCVS type IN (irregular and nebulous), indigenous to star-forming regions, may vary by several magnitudes with rapid changes of up to 1 magnitude in 1 to 10 days, are similarly divided by spectral type into subgroups INA and INB, but with the addition of another subgroup, INT, for T Tauri stars, or INT(YY) for YY Orionis stars. * The third category of eruptive irregulars are the IS stars, which show rapid variations of 0.5 to 1 magnitude in a few hours or days; again, these come in subgroups ISA and ISB. Pulsating irregular giants or supergiants, called slow irregular variable A slow irregular variable ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K-type Giants
K-type may refer to: *AEC K-type The AEC K-type was a type of bus chassis built by Associated Equipment Company (AEC) from 1919 until 1926, mainly for use in London by the London General Omnibus Company (LGOC). Description The K-type was an important design that ended the ..., a bus chassis * K-type star, a stellar spectral classification * K-type filter, a type of electronic filter * K-type asteroid, an unusual kind of asteroid {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monthly Notices Of The Royal Astronomical Society
''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal in astronomy, astrophysics and related fields. It publishes original research in two formats: papers (of any length) and letters (limited to five pages). MNRAS publishes more articles per year than any other astronomy journal. The learned society journal has been in continuous existence since 1827 and became online only in 2020. It operates as a partnership between the Royal Astronomical Society (RAS), who select and peer-review the contents, and Oxford University Press (OUP), who publish and market the journal. Despite its name, MNRAS is no longer monthly, nor does it carry the notices of the RAS. In 2024 MNRAS became a purely gold open access journal. History The first issue of MNRAS was published on 9 February 1827 as ''Monthly Notices of the Astronomical Society of London'' and it has been in continuous publication ever since. It took its current name from the second vo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective Temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature when the body's emissivity curve (as a function of wavelength) is not known. When the star's or planet's net emissivity in the relevant wavelength band is less than unity (less than that of a black body), the actual temperature of the body will be higher than the effective temperature. The net emissivity may be low due to surface or atmospheric properties, such as the greenhouse effect. Star The effective temperature of a star is the temperature of a black body with the same luminosity per ''surface area'' () as the star and is defined according to the Stefan–Boltzmann law . Notice that the total ( bolometric) luminosity of a star is then , where is the stellar radius. The definition of the stellar radius is obviously not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosphere
The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will escape without being scattered. A photosphere is the region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Stars, except neutron stars, have no solid or liquid surface. Therefore, the photosphere is typically used to describe the Sun's or another star's visual surface. Etymology The term ''photosphere'' is derived from Ancient Greek roots, φῶς, φωτός/''phos'', ''photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. Various stars have photospheres of vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
