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Alrescha
Alpha Piscium (α Piscium) is a binary star system in the equatorial constellation of Pisces. Based upon parallax measurements made by the Hipparcos spacecraft, it is about from the Solar System. The two components are designated Alpha Piscium A (officially named Alrescha, the traditional name of the system) and B. Nomenclature ''α Piscium'' ( Latinised to ''Alpha Piscium'') is the star's Bayer designation. The designations of the two components as ''Alpha Piscium 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). The system bore the traditional name ''Alrescha'' (alternatively ''Al Rescha'', ''Alrischa'', ''Alrisha'') derived from the Arabic الرشآء ''al-rishā’'' "the cord" and less commonly ''Kaitain'' and ''Okda'', the latter from the Arabic عقدة ''ʽuqdah'' "knot" (see Ukdah. In 2016, the International Astronomical Union ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pisces (constellation)
Pisces is a constellation of the zodiac. Its vast bulk – and main asterism viewed in most European cultures per Greco-Roman antiquity as a distant pair of fishes connected by one cord each that join at an apex – are in the Northern celestial hemisphere. Its old astronomical symbol is (♓︎). Its name is Latin for "fishes". It is between Aquarius, of similar size, to the southwest and Aries, which is smaller, to the east. The ecliptic and the celestial equator intersect within this constellation and in Virgo. This means the sun passes directly overhead of the equator, on average, at approximately this point in the sky, at the March equinox. Features The March equinox is currently located in Pisces, due south of ω Psc, and, due to precession, slowly drifting due west, just below the western fish towards Aquarius. Stars * Alrescha ("the cord"), otherwise Alpha Piscium (α Psc), 309.8 lightyears, class A2, magnitude 3.62. Variable binary star. * Fuma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha2 Canum Venaticorum Variable
An Alpha2 Canum Venaticorum variable (or α2 CVn variable) is a type of variable star. These stars are chemically peculiar main sequence stars of spectral class B8p to A7p. They have strong magnetic fields and strong silicon, strontium, or chromium spectral lines. Their brightness typically varies by 0.01 to 0.1 magnitudes over the course of 0.5 to 160 days. In addition to their intensities, the intensities and profiles of the spectral lines of α2 CVn variables also vary, as do their magnetic fields. The periods of these variations are all equal and are believed to equal the period of rotation of the star. It is thought that they are caused by an inhomogeneous distribution of metals in the atmospheres of these stars, so that the surface of the star varies in brightness from point to point. The type-star which this class is named after is α² Canum Venaticorum, a star in the binary system of Cor Caroli, which is in the northern constellation of Canes Venatici Canes Ven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Star Names
Chinese star names ( Chinese: , ''xīng míng'') are named according to ancient Chinese astronomy and astrology. The sky is divided into star mansions (, ''xīng xiù'', also translated as "lodges") and asterisms (, ''xīng guān''). The system of 283 asterisms under Three Enclosures and Twenty-eight Mansions was established by Chen Zhuo of the Three Kingdoms period, who synthesized ancient constellations and the asterisms created by early astronomers Shi Shen, Gan De and Wuxian. Since the Han and Jin Dynasties, stars have been given reference numbers within their asterisms in a system similar to the Bayer or Flamsteed designations, so that individual stars can be identified. For example, Deneb (α Cyg) is referred to as (''Tiān Jīn Sì'', the Fourth Star of Celestial Ford). In the Qing Dynasty, Chinese knowledge of the sky was improved by the arrival of European star charts. ''Yixiang Kaocheng'', compiled in mid-18th century by then deputy Minister of Rites Ignaz Kö ... [...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 the positions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Astronomy
Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twenty-eight mansions have been found on oracle bones unearthed at Anyang, dating back to the mid-Shang dynasty. The core of the "mansion" (宿 ''xiù'') system also took shape around this period, by the time of King Wu Ding (1250–1192 BCE). Detailed records of astronomical observations began during the Warring States period (fourth century BCE) and flourished from the Han period onward. Chinese astronomy was equatorial, centered on close observation of circumpolar stars, and was based on different principles from those in traditional Western astronomy, where heliacal risings and settings of zodiac constellations formed the basic ecliptic framework. Joseph Needham has described the ancient Chinese as the most persistent and accurat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Classification
In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary mainly due to the temperature of the photosphere, although in some cases there are true abundance differences. The ''spectral class'' of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature. Most stars are currently classified under the Morgan–Keenan (MK) system using the letters ''O'', ''B'', ''A'', ''F'', ''G'', ''K'', and ''M'', a sequence from the hottest (''O'' type) to the coolest (''M'' type). Each letter class is then subdivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's light caused by interstellar dust along the line of sight to the observer. The word ''magnitude'' in astronomy, unless stated otherwise, usually refers to a celestial object's apparent magnitude. The magnitude scale dates back to the ancient Roman astronomer Claudius Ptolemy, whose star catalog listed stars from 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined in a way to closely match this historical system. The scale is reverse logarithmic: the brighter an object is, the lower its magnitude number. A difference of 1.0 in magnitude corresponds to a brightness ratio of \sqrt /math>, or about 2.512. For example, a star of magnitude 2.0 is 2.512 times as bright as a star of magnitude 3.0 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Distance
Angular distance \theta (also known as angular separation, apparent distance, or apparent separation) is the angle between the two sightlines, or between two point objects as viewed from an observer. Angular distance appears in mathematics (in particular geometry and trigonometry) and all natural sciences (e.g. astronomy and geophysics). In the classical mechanics of rotating objects, it appears alongside angular velocity, angular acceleration, angular momentum, moment of inertia and torque. Use The term ''angular distance'' (or ''separation'') is technically synonymous with ''angle'' itself, but is meant to suggest the linear distance between objects (for instance, a couple of stars observed from Earth). Measurement Since the angular distance (or separation) is conceptually identical to an angle, it is measured in the same units, such as degrees or radians, using instruments such as goniometers or optical instruments specially designed to point in well-defined directions an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xi Piscium
Xi Piscium (ξ Piscium) is an orange-hued binary star system in the zodiac constellation of Pisces. In 1690, the astronomer Johannes Hevelius in his ''Firmamentum Sobiescianum'' regarded the constellation Pisces as being composed of four subdivisions. Xi Piscium was considered to be part of the ''Linum Austrinum'', the South Cord. The star is visible to the naked eye, having an apparent visual magnitude of 4.60. Based upon an annual parallax shift of 11.67 mas as seen from Earth, it is located about 280 light years from the Sun. It is moving away from the Sun, having a radial velocity of +26 km/s. This is a single-lined spectroscopic binary system with an orbital period of 4.6 years and an eccentricity of around 0.18. The spectroscopic binary nature of this star was discovered in 1901 by William Wallace Campbell using the Mills spectrograph at the Lick Observatory. The visible component is an evolved K-type giant star with a stellar classifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nu Piscium
Nu Piscium (ν Piscium) is an orange-hued binary star system in the zodiac constellation of Pisces. Prior to the formation of the modern constellation boundaries in 1930, it was designated 51 Ceti in the Cetus constellation. Nu Piscium is visible to the naked eye, having a combined apparent visual magnitude of 4.44. Based upon an annual parallax shift of 8.98 mas as seen from Earth, it is located about 363 light years from the Sun. The primary, component A, is an evolved, K-type giant star with a stellar classification of K3 IIIb. It is a weak barium star, indicating that the atmosphere was previously enriched by accretion of s-process elements from what is now a white dwarf companion. The giant has 1.66 times the mass of the Sun and has expanded to about 34 times the Sun's radius. It is about 3.4 billion years old and is radiating 380 times the Sun's luminosity from its photosphere at an effective temperature of 4,154 K. Naming In Chinese, ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mu Piscium
Mu Piscium (μ Piscium) is a solitary, orange-hued star in the zodiac constellation of Pisces. It is visible to the naked eye with an apparent visual magnitude of 4.84. Based upon an annual parallax shift of 10.73 mas as seen from Earth, it is located about 304 light years from the Sun. Given this distance, it has a relatively high proper motion, advancing 296 mas per year across the sky. This is an evolved K-type giant star with a stellar classification of K4 III. It has an estimated 1.25 times the mass of the Sun and, at the age of 5.6 billion years, has expanded to about 37 times the Sun's radius. From this enlarged photosphere, it is radiating 186 times the Sun's luminosity at an effective temperature of 4,126 K. It has a magnitude 12.02 visual companion at an angular separation of 209.30 arc seconds along a position angle of 298°, as of 2012. Naming In Chinese, (), meaning '' Outer Fence'', refers to an asterism consisting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeta Piscium
Zeta Piscium (ζ Piscium, abbreviated Zet Psc, ζ Psc) is a quintuple star system in the zodiac constellation of Pisces. Based upon parallax measurements obtained during the Hipparcos mission, it is located roughly distant from the Sun. The system consists of a binary star (Zeta Piscium A) and a triple star system (BC), the latter consisting of a spectroscopic binary (B) and a single star (C). A's two components are themselves designated Zeta Piscium Aa (officially named Revati ) and Ab; B's two components as Ba and Bb. As the star system is 0.21° south of the ecliptic, it can be eclipsed ( occulted) by the moon, when close to or at one of its two nodes of its orbit; and is eclipsed by the sun from about 8-10 April. Nomenclature ''ζ Piscium'' ( Latinised to ''Zeta Piscium'') is the system's Bayer designation. The designations of the three constituents as ''Zeta Piscium A'', ''B'' and ''C'', and those of ''A's'' and ''B's'' components - ''Zeta Piscium Aa'', ''Ab'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
