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Alpha Piscium
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] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IAU Working Group On Star Names
The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education, Outreach and Heritage. The IAU states that it is keen to make a distinction between the terms ''name'' and ''designation''. To the IAU, ''name'' refers to the (usually colloquial) term used for a star in everyday conversation, while ''designation'' is solely alphanumerical, and used almost exclusively in official catalogues and for professional astronomy. (The WGSN notes that transliterated Bayer designations (e.g., Tau Ceti) are considered a special historical case and are treated as designations.) Terms of reference The terms of reference for the WGSN for the period 2016–2018 were approved by the IAU Executive Committee at its meeting on 6 May 2016. In summary, these are to: * establish IAU guidelines for the proposal and ... [...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 and re ... [...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 K� ... [...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 clas ... [...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 Chi ... [...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 con ... [...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'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epsilon Piscium
Epsilon Piscium (Epsilon Psc, ε Piscium, ε Psc) is the Bayer designation for a star approximately away from the Earth, in the constellation Pisces. It is a yellow-orange star of the G9 III or K0 III spectral type, meaning it has a surface temperature around 5,000 kelvins. This is a normal giant star, slightly cooler in surface temperature, yet brighter and larger than the Sun. It is a suspected occultation double, with both stars having the same magnitude, separated by 0.25 arcsecond. Naming In Chinese, (), meaning '' Outer Fence'', refers to an asterism consisting of ε Piscium, δ Piscium, ζ Piscium, μ Piscium, ν Piscium, ξ Piscium and α Piscium. Consequently, the Chinese name for ε Piscium itself is (, en, the Second Star of Outer Fence.) In Japanese, 悠翔星 (Haruto-boshi), meaning "Soaring Forever Star," refers to the Japanese description of ε Piscium. Planetary system In 2021, a gas giant planetary candidate was de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta Piscium
Delta Piscium (δ Piscium) is a solitary, orange-hued star in the zodiac constellation of Pisces. It has an apparent visual magnitude of +4.4, so it is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of 10.5 mas, it is around from the Sun. The visual magnitude of the star is diminished by an interstellar absorption factor of 0.08 due to interstellar dust. This is an evolved K-type giant star with a stellar classification of K4 IIIb. It has around 1.65 times the mass of the Sun and, at the age of three billion years, has expanded to 44 times the Sun's radius. The star is radiating 447 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,963 K. Because Delta Piscium is positioned near the ecliptic, so it is subject to lunar occultations. It has a magnitude 13.99 visual companion at an angular separation of 135.0 arc seconds on a position angle of 12°, as of 2011. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
