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ζ Virginis
Zeta Virginis (ζ Virginis, abbreviated Zeta Vir, ζ Vir) is a binary star in the zodiac constellation of Virgo. It is visible to the naked eye with an apparent visual magnitude of +3.376 and is located about a half degree south of the celestial equator. Based on parallax measurements obtained during the Hipparcos mission, it is about distant from the Sun. The two components are designated Zeta Virginis A (officially named Heze , a mid-20th-century name for the system) and B. Nomenclature ''ζ Virginis'' ( Latinised to ''Zeta Virginis'') is the system's Bayer designation. The designations of the two components as ''Zeta Virginis 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). Zeta Virginis bore the name ''Heze'' in a 1951 publication, ''Atlas Coeli'' ( Skalnate Pleso Atlas of the Heavens), by Czech astronomer Antonín Bečvář. Its origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virgo (constellation)
Virgo is one of the constellations of the zodiac. The name is for maiden in Latin and its traditional astrological symbol is . Between Leo (constellation), Leo to the west and Libra (constellation), Libra to the east, lying in the south, it is the second-largest constellation in the sky (after Hydra (constellation), Hydra) and the largest constellation in the zodiac. The ecliptic intersects the celestial equator within this constellation and Pisces (constellation), Pisces. Underlying these technical two definitions, the sun passes directly overhead of the equator, within this constellation, at the September equinox. Virgo can be easily found through its brightest star, Spica, (in Latin "grain headed"). Location Virgo is prominent in the spring sky in the Northern Hemisphere, visible all night in March and April. As the largest zodiac constellation, the Sun takes 44 days to pass through it, longer than any other. From 1990 and until 2062, this will take place from September 16 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antonín Bečvář
Antonín Bečvář (; 10 June 1901 – 10 January 1965) was a Czechoslovak astronomer. Biography He was born and died in Stará Boleslav. Among his chief achievements is the foundation of the Skalnaté Pleso Observatory and the discovery of the comet C/1947 F2 (Bečvář) (also known by the designations 1947 III and 1947c). His lifelong illness led him to the High Tatras where he founded the observatory. Bečvář is particularly important for his star charts: he led the compilation of the ''Atlas Coeli Skalnate Pleso'' (1951), published by Sky Publishing Corporation as the '' Skalnate Pleso Atlas of the Heavens'', which was the state-of-the-art atlas of its kind until Wil Tirion's "Sky Atlas 2000.0" in 1981. A dozen star names in the atlas are of unknown origin, no connection to any language or previous source has been discovered despite an extensive search. He also compiled ''Atlas eclipticalis, 1950.0'' (1958), ''Atlas borealis 1950.0'' (1962), and ''Atlas australis 195 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Radius
Solar radius is a unit of distance used to express the size of objects in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: 1\,R_ = 6.957\times 10^8 \hbox is approximately 10 times the average radius of Jupiter, 109 times the radius of the Earth, and 1/215 of an astronomical unit, the approximate distance between Earth and the Sun. The solar radius to either pole and that to the equator differ slightly due to the Sun's rotation, which induces an oblateness in the order of 10 parts per million. Measurements The uncrewed SOHO spacecraft was used to measure the radius of the Sun by timing transits of Mercury across the surface during 2003 and 2006. The result was a measured radius of . Haberreiter, Schmutz & Kosovichev (2008) determined the radius corresponding to the solar photosphere to be . This new value is consistent with helioseismic estimates; the same study sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Mass
The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. More precisely, the mass of the Sun is The solar mass is about times the mass of Earth (), or times the mass of Jupiter (). History of measurement The value of the gravitational constant was first derived from measurements that were made by Henry Cavendish in 1798 with a torsion balance. The value he obtained differs by only 1% from the modern value, but was not as precise. The diurnal parallax of the Sun was accurately measured during the transits of Venus in 1761 and 1769, yielding a value of (9 arcseconds, compared to the present value of ). From the value of the diurnal parallax, one can determine the distance to the Sun from the geometry of Earth. The first known estimate of the solar mass was by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A-type Star
A type or type A may refer to: Science * A-type asteroid, a type of relatively uncommon inner-belt asteroids * A type blood, a type in the ABO blood group system * A-type inclusion, a type of cell inclusion * A-type potassium channel, a type of voltage-gated potassium channel * A type proanthocyanidin, a specific type of flavonoids * A-type star, a class of stars * Type A climate, a type in the Köppen climate classification * Type A flu, a type of influenza virus * Type A evaluation of uncertainty, an uncertainty in measurement that can be inferred, for example, from repeated measurement * Type A personality, a personality type in the Type A and Type B personality theory * Hemophilia type A, a type of haemophilia * A-type granite a type of granite rock * Adenosine receptor The adenosine receptors (or P1 receptors) are a class of Purinergic receptor, purinergic G protein-coupled receptors with adenosine as the endogenous ligand (biochemistry), ligand. There are four kno ... [...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] |
Nuclear Fusion
Nuclear fusion is a nuclear reaction, reaction in which two or more atomic nuclei combine to form a larger nuclei, nuclei/neutrons, neutron by-products. The difference in mass between the reactants and products is manifested as either the release or absorption (electromagnetic radiation), absorption of energy. This difference in mass arises as a result of the difference in nuclear binding energy between the atomic nuclei before and after the fusion reaction. Nuclear fusion is the process that powers all active stars, via many Stellar nucleosynthesis, reaction pathways. Fusion processes require an extremely large Lawson criterion, triple product of temperature, density, and confinement time. These conditions occur only in Stellar core, stellar cores, advanced Nuclear weapon design, nuclear weapons, and are approached in List of fusion experiments, fusion power experiments. A nuclear fusion process that produces atomic nuclei lighter than nickel-62 is generally exothermic, due t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Classification
In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grating into a spectrum exhibiting the Continuum (spectrum), 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 cool ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Main Sequence
In astronomy, the main sequence is a classification of stars which appear on plots of stellar color index, color versus absolute magnitude, brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or dwarf stars, and positions of stars on and off the band are believed to indicate their physical properties, as well as their progress through several types of star life-cycles. These are the most numerous true stars in the universe and include the Sun. Color-magnitude plots are known as Hertzsprung–Russell diagrams after Ejnar Hertzsprung and Henry Norris Russell. After condensation and ignition of a star, it generates thermal energy in its dense stellar core, 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 hydros ... [...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 ecliptic is divided into four sectors that are associated with the Four Symbols, guardians in Chinese mythology, and further into 28 mansions. Stars around the north celestial pole are grouped into three enclosures (, ''yuán''). The system of 283 asterisms under the 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 S� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spica
Spica is the brightest object in the constellation of Virgo and one of the 20 brightest stars in the night sky. It has the Bayer designation α Virginis, which is Latinised to Alpha Virginis and abbreviated Alpha Vir or α Vir. Analysis of its parallax shows that it is located 250 light-years from the Sun. It is a spectroscopic binary star and rotating ellipsoidal variable; a system whose two stars are so close together they are egg-shaped rather than spherical, and can only be separated by their spectra. The primary is a blue giant and a variable star of the Beta Cephei type. Spica, along with Arcturus and Denebola—or Regulus, depending on the source—forms the Spring Triangle asterism, and, by extension, is also part of the Great Diamond together with the star Cor Caroli. Nomenclature In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horn (Chinese Constellation)
The Horn mansion (角宿, pinyin: Jiǎo Xiù) is one of the Twenty-eight mansions of the Chinese constellations. It is one of the eastern mansions of the Azure Dragon The Azure Dragon ( zh, c=青龍, p=Qīnglóng) is one of the Dragon King, Dragon Gods who represent the mount or Chthonic deities, chthonic forces of the Wufang Shangdi, Five Regions' Highest Deities (). It is also one of the Four Symbols o .... Asterisms References {{DEFAULTSORT:Horn (Chinese Constellation) Chinese constellations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
