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Eta2 Doradus
Eta2 Doradus, Latinized from η2 Doradus, is a star in the southern constellation of Dorado. It is visible to the naked eye as a dim, reddish star with an apparent visual magnitude of 5.01 It is about 580 light years from the Sun as shown by parallax, and its net movement is one of receding, having a radial velocity of +34.5 km/s. It is circumpolar south of latitude S. This object is an M-type giant star, with its stellar classification being M2.5III. It has left the main sequence after exhausting its core hydrogen and expanded to around . The star is radiating about 1200 times the Sun's luminosity from its photosphere, at an effective temperature of 3726 K. References External links * 2004. Starry Night Pro, Version 5.8.4. Imaginova Imaginova Corporation is a U.S. digital commerce company based in Watsonville, California. The company, which was started in 1999 as "Space.com" by CNN business anchor Lou Dobbs, later became known as Space H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a instant, moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a Astronomical object, celestial body, as they are subject to Perturbation (astronomy), perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or Perihelion and aphelion, aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sun's Luminosity
The solar luminosity (), is a unit of radiant flux (power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal solar luminosity is defined by the International Astronomical Union to be . This does not include the solar neutrino luminosity, which would add , or , i.e. a total of (the mean energy of the solar photons is 26 MeV and that of the solar neutrinos 0.59 MeV, i.e. 2.27%; the Sun emits photons and as many neutrinos each second, of which per m2 reach the Earth each second). The Sun is a weakly variable star, and its actual luminosity therefore fluctuates. The major fluctuation is the eleven-year solar cycle (sunspot cycle) that causes a quasi-periodic variation of about ±0.1%. Other variations over the last 200–300 years are thought to be much smaller than this. Determination Solar luminosity is related to solar irradiance (the sola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorado
Dorado () is a constellation in the southern sky. It was named in the late 16th century and is now one of the 88 modern constellations. Its name refers to the dolphinfish (''Coryphaena hippurus''), which is known as ''dorado'' in Spanish, although it has also been depicted as a swordfish. Dorado contains most of the Large Magellanic Cloud, the remainder being in the constellation Mensa. The South Ecliptic pole also lies within this constellation. Even though the name Dorado is not Latin but Spanish, astronomers give it the Latin genitive form ''Doradus'' when naming its stars; it is treated (like the adjacent asterism Argo Navis) as a feminine proper name of Greek origin ending in -ō (like ''Io'' or ''Callisto'' or ''Argo''), which have a genitive ending ''-ūs''. History Dorado was one of twelve constellations named by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. It appeared: * On a celestial globe published in 1597 (or 1598) ... [...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, compiled by the Bonn Observatory in Germany from 1859 to 1903. 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 wavelengths shorter or longer than visible light waves. Original catalog The 44 years of work on the Bonner Durchmusterung (abbreviated BD), initiated by Friedrich Argelander and largely carried out by his assistants, resulted in a catalogue of the positions and apparent magnitudes of approximately 325,000 stars to apparent magnitude 9–10. The catalogue was accompanied by charts plotting the positions of the stars, and was the basis for the ''Astronomische Gesellschaft Katalog'' (AGK) and ''Smithsonia ... [...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 of celestial objects on the sky. This permitted the first high-precision measurements of the intrinsic brightnesses (compared to the less precise apparent brightness), 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'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Draper Catalogue Objects
Henry may refer to: People *Henry (given name) *Henry (surname) * Henry Lau, Canadian singer and musician who performs under the mononym Henry Royalty * Portuguese royalty ** King-Cardinal Henry, King of Portugal ** Henry, Count of Portugal, Henry of Burgundy, Count of Portugal (father of Portugal's first king) ** Prince Henry the Navigator, Infante of Portugal ** Infante Henrique, Duke of Coimbra (born 1949), the sixth in line to Portuguese throne * King of Germany ** Henry the Fowler (876–936), first king of Germany * King of Scots (in name, at least) ** Henry Stuart, Lord Darnley (1545/6–1567), consort of Mary, queen of Scots ** Henry Benedict Stuart, the 'Cardinal Duke of York', brother of Bonnie Prince Charlie, who was hailed by Jacobites as Henry IX * Four kings of Castile: **Henry I of Castile **Henry II of Castile **Henry III of Castile **Henry IV of Castile * Five kings of France, spelt ''Henri'' in Modern French since the Renaissance to italianize the name and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M-type Giants
Type M or M type may refer to: Science and technology * Type M, a xD-Picture Card * Type M, a name for the 15 amp BS 546 electrical plug * Vaio Type M, a kind of Vaio computer from Sony * M-type asteroid * m-type filter, an electronic filter * M-type star * M-types, an implementation of inductive type Other uses * Audi Type M, a 1920s car * Beretta 92FS Compact Type M, a pistol * MG M-type, a sports car See also * M class (other) M class or M-class may refer to: Military * M-class cruiser, a planned German light cruiser class * M-class destroyer, several classes of destroyer ** Admiralty M-class destroyer, a class of British destroyers built 1913–1916 and served in Worl ... * Class M (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imaginova
Imaginova Corporation is a U.S. digital commerce company based in Watsonville, California. The company, which was started in 1999 as "Space.com" by CNN business anchor Lou Dobbs, later became known as Space Holdings Corp. Dan Stone became President, Chief Executive Officer and a board member in 2002 and renamed the company to Imaginova in 2004. The company sold its consumer businesses to TechMediaNetwork, formally TopTenReviews, in 2009. ''Imaginova'' promotes itself as the preeminent destination for the “intellectually curious.” It comprises the following E-Commerce retailers: space * LiveScienceStore.com LiveScienceStore.com * Orion Telescopes & Binoculars OrionTelescopes.com ''Imaginova'' previously owned SpaceNews until it was sold to Pocket Ventures, LLC. in 2012. ''Imaginova'' is a news provider, via the Imaginova Network of media properties, and syndicates its original content to the following news portals: Yahoo!, MSNBC, AOL and FoxNews.com. ''Imaginova'' was t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starry Night (planetarium Software)
''The Starry Night'' ( nl, De sterrennacht) is an oil-on-canvas painting by the Dutch Post-Impressionist painter Vincent van Gogh. Painted in June 1889, it depicts the view from the east-facing window of his asylum room at Saint-Rémy-de-Provence, just before sunrise, with the addition of an imaginary village. It has been in the permanent collection of the Museum of Modern Art in New York City since 1941, acquired through the Lillie P. Bliss Bequest. Widely regarded as Van Gogh's magnum opus, ''The Starry Night'' is one of the most recognizable paintings in Western art. The asylum In the aftermath of the 23 December 1888 breakdown that resulted in the self-mutilation of his left ear, Van Gogh voluntarily admitted himself to the Saint-Paul-de-Mausole lunatic asylum on 8 May 1889. Housed in a former monastery, Saint-Paul-de-Mausole catered to the wealthy and was less than half full when Van Gogh arrived, allowing him to occupy not only a second-story bedroom but also a ground-flo ... [...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, including 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 straightf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosphere
The photosphere is a star's outer shell from which light is radiated. The term itself 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. 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 deepest region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. 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. Composition of the Sun The Sun is composed primarily of ... [...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] |
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