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μ Persei
Mu Persei, Latinised from μ Persei, is a binary star system in the northern constellation of Perseus. It is visible to the naked eye as a point of light with a combined apparent visual magnitude of +4.16. The distance to this system is approximately 900 light-years based on parallax measurements. It is drifting further away with a radial velocity of +26 km/s. Mu Persei is a spectroscopic binary with an orbital period of 284 days and an eccentricity of about 0.06. The primary component is a yellow G-type supergiant star. With an effective temperature of about and a radius of 53 solar radii, this star has the luminosity of about 2,030 times that of the Sun. The companion is a B-type star with a class of B9.5 Mu Persei is moving through the galaxy at a speed of 35.6 km/s relative to the Sun. Its projected galactic orbit carries it between 23,900 and 32,400 light-years from the center of the galaxy. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a 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 celestial body, as they are subject to 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 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 bodies) can be used to generate an ephemeris, a table of values giving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Luminosity
The solar luminosity () is a unit of radiant flux (Power (physics), power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxy, 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 corresponds almost exactly to a bolometric magnitude, bolometric absolute magnitude of +4.74. The Sun is a weakly variable star, and its actual luminosity therefore Solar variation, 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 Irradiance, solar irradiance (the solar constant). Slow changes in the axial tilt of the planet and the shape of its orbit cause cyclical changes to the solar irradiance. The result is orb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectroscopic Binaries
A binary star or binary star system is a Star system, system of two stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars using a telescope, in which case they are called ''visual binaries''. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (''spectroscopic binaries'') or astrometry (''astrometric binaries''). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit (astronomy), transit each other; these pairs are called ''eclipsing binaries'', or, together with other binaries that change brightness as they orbit, ''photometric binaries''. If components in binary star systems are close enough, they can gravitationally distort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G-type Supergiants
G-Type G-Type is a fictional character from Marvel Comics. G-Type is one of the Shi'ar's Imperial Guard, and is also an alien. He was engineered in the stellar nurseries of Hodinn and was composed of a living solar plasma, with a constant surface temperature of 6000 kelvins (about 10,000 degrees Fahrenheit or 5,700 degrees Celsius). Because of this G-Type wears specially-constructed armor which assists him in retaining a humanoid form and contains the heat that he generates. G-Type is also a telepath, although the nature and extent of his telepathy are unknown. Similar to the other Imperial Guard members, he is based on DC Comics' Legion of Super-Heroes, sharing traits with Wildfire and Saturn Girl. His mind, like the minds of many other Shi'ar soldiers, was overtaken by the telepath Cassandra Nova. He was defeated by Cyclops and Xorn, whom he was planning to fire into the Earth's atmosphere. Gaea Gaea is a fictional character appearing in American comic books pub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 27084
HD may refer to: Business * H-D or Harley-Davidson, a motorcycle manufacturer * The Home Depot, NYSE stock symbol: HD Chemistry * Hydrogen deuteride, a diatomic compound of hydrogen and deuterium * Mustard gas Codes * Air Do, formerly Hokkaido International Airlines, IATA designator * HD postcode area, covering Huddersfield, Brighouse and Holmfirth in England, UK * Heidelberg's vehicle registration plate code * Hunedoara County (Romania)'s ISO 3166 code Medicine * Hansen's disease or leprosy * Hirschsprung's disease, a disorder of the abdomen * Huntington's disease, a genetic disorder affecting the central nervous system ** HD (gene) or huntingtin, the IT15 gene, which codes for the huntingtin protein People * H.D. or Hilda Doolittle (1886–1961), American poet and novelist Other uses * ''Helsingborgs Dagblad'', a Swedish newspaper * Henry Draper Catalogue, an astronomical catalogue often used to designate stars * Department of Highways (other) * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
48 Persei
48 Persei (also known as c Persei, 48 Per, HR 1273, HIP 19343, or ) is a Be star in the constellation Perseus, approximately the 500th brightest of the visible stars in apparent magnitude. It is "well known for its complex spectrum and for its light and velocity variations". The name "48 Persei" is a Flamsteed designation given to it by John Flamsteed in his catalogue, published in 1712. 48 Persei is classified as a Gamma Cassiopeiae variable, and it has been given the variable star designation MX Persei. The star's brightness varies by 0.09 magnitudes in visible light. Koen and Eyer examined the Hipparcos ''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 ... data for this star, and found it varied with a period of 5.0569 days. As a Be star, it is hot and blue, spinni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
δ Persei
Delta Persei (Delta Per, δ Persei, δ Per) is a double star in the northern constellation of Perseus. It has an apparent visual magnitude of 3.01, making it readily visible with the naked eye. Parallax measurements give it a distance of about from the Earth. The spectrum of this star matches a stellar classification of B5 III, which indicates it is a giant star that has evolved away from the main sequence after exhausting the hydrogen at its core. It has about seven times the Sun's mass and has an estimated age of 6.8 million years. The effective temperature of the outer envelope is 14,890 K, with the energy being emitted at this temperature giving it the blue-white hue that is a characteristic of a B-type star. It is rotating rapidly with a projected rotational velocity of 190 km s−1, which gives a lower bound for the actual azimuthal velocity along the star's equator. This is most probably a binary star and may be a triple star syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ψ Persei
Psi Persei (Psi Per, ψ Persei, ψ Per) is a single Be star in the northern constellation of Perseus. It has an apparent visual magnitude of about 4.2, so it is visible to the naked eye at night under suitably dark skies. Based on parallax measurements, it is located at a distance of roughly from the Earth. Properties This star has a stellar classification of B5Ve, which indicates it is a B-type main sequence star that is generating energy at its core through the nuclear fusion of hydrogen. It is a shell star with a circumstellar disc of gas surrounding the equator and extending out to about 11 times the radius of the star. As a result of this disc, the spectrum of this star shows emission lines (as indicated by the 'e' in the stellar class) and its magnitude varies over a period 1.021 days. The General Catalog of Variable Stars classifies Psi Persei as a gamma Cassiopeiae variable star, whose visual band brightness varies from magnitude 4.17 to 4. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
α Persei
Alpha Persei ( Latinized from α Persei, abbreviated Alpha Per, α Per), formally named Mirfak (pronounced or ), is the brightest star in the northern constellation of Perseus, outshining the constellation's best-known star, Algol (β Persei). Alpha Persei has an apparent visual magnitude of 1.8, and is a circumpolar star when viewed from mid-northern latitudes. Alpha Persei lies in the midst of a cluster of stars named as the eponymous Alpha Persei Cluster, or ''Melotte 20'', which is easily visible in binoculars and includes many of the fainter stars in the constellation. Determined distance using the trigonometric parallax, places the star away. Nomenclature ''α Persei'' is the star's Bayer designation. The star also bore the traditional names Mirfak and Algenib, which are Arabic in origin. The former, meaning 'Elbow' and also written Mirphak, Marfak or Mirzac, comes from the Arabic ''Mirfaq al-Thurayya'', while Algenib, also spelt Algeneb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
γ Persei
Gamma Persei (Gamma Per, γ Persei, γ Per) is a binary star system in the constellation Perseus (constellation), Perseus. The combined apparent visual magnitude of the pair is +2.9, making it the fourth-brightest member of the constellation. The distance to this system is of roughly with a 1% margin of error. About 4° to the north of Gamma Persei is the radiance point for the annual Perseid meteor shower. This is a wide Binary star#Eclipsing binaries, eclipsing binary system with an orbital period of 5,329.8 days (14.6 years). This eclipse was first observed in 1990 and lasted for two weeks. During an eclipse, the primary passes in front of the secondary, causing the magnitude of the system to decrease by 0.55. The primary component of this system is a giant star with a stellar classification of G9 III. It has a projected rotational velocity of 50.0 km s−1 and a lengthy estimated rotation period of 14.6 years. The classification of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
η Persei
Eta Persei (η Persei, abbreviated Eta Per, η Per), is a red supergiant in the constellation of Perseus. Parallax measurements by the Gaia spacecraft imply that it is 1,000 is light-years away from Earth. At such distance, interstellar dust diminishes its apparent brightness by 0.47 magnitudes. The two components of Eta Persei itself are designated Eta Persei A (officially named Miram , a recent name for the system) and B. Nomenclature ''η Persei'' ( Latinised to ''Eta Persei'') is the binary star's Bayer designation. The designations of its two components as ''Eta Persei A'' and ''B'' derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU). Eta Persei mysteriously gained the named ''Miram'' in the 20th Century, though no source is known. In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterism (astronomy)
An asterism is an observational astronomy, observed pattern or group of stars in the sky. Asterisms can be any identified star pattern, and therefore are a more general concept than the IAU designated constellations, 88 formally defined constellations. Constellations are based upon asterisms, but unlike asterisms, constellations are defined regions with official boundaries which together encompass the entire sky. Asterisms range from simple shapes of just a few stars to more complex collections of many stars covering large portions of the sky. The stars themselves may be bright naked-eye objects or fainter, even telescopic, but they are generally all of a similar brightness to each other. The larger brighter asterisms are useful for people who are familiarizing themselves with the night sky. The patterns of stars seen in asterisms are not necessarily a product of any physical association between the stars, but are rather the result of the particular perspectives of their observ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
