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Alpha Coronae Australis
Alpha Coronae Australis or α Coronae Australis, officially named Meridiana (), is the brightest star in the constellation of Corona Australis and is located about 125 light-years from Earth. Nomenclature ''α Coronae Australis'' ( Latinised to ''Alpha Coronae Australis'') is the star's Bayer designation. It is the only star in the constellation with a traditional proper name, ''Alphekka Meridiana'' (Latin for 'Alphekka South'), after ''Alphecca'', the brightest star in the constellation Corona Borealis. The name ''Alphecca'' or ''Alphekka'' is Arabic, short for نير الفكّة ''nayyir al-fakka'' "the bright (star) of the broken (ring of stars)". In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN approved the name ''Meridiana'' for this star on 5 September 2017 and it is now so included in the List of IAU-approved Star Names. In Chinese, (), meaning '' River Turtle'', refers to an asteris ... [...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] |
Dover Publications
Dover Publications, also known as Dover Books, is an American book publisher founded in 1941 by Hayward and Blanche Cirker. It primarily reissues books that are out of print from their original publishers. These are often, but not always, books in the public domain. The original published editions may be scarce or historically significant. Dover republishes these books, making them available at a significantly reduced cost. Classic reprints Dover reprints classic works of literature, classical sheet music, and public-domain images from the 18th and 19th centuries. Dover also publishes an extensive collection of mathematical, scientific, and engineering texts. It often targets its reprints at a niche market, such as woodworking. Starting in 2015, the company branched out into graphic novel reprints, overseen by Dover acquisitions editor and former comics writer and editor Drew Ford. Most Dover reprints are photo facsimiles of the originals, retaining the original pagination and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epsilon Coronae Australis
Epsilon Coronae Australis (ε CrA), is a star system located in the constellation Corona Australis. Varying in brightness between apparent magnitudes of 4.74 to 5 over 14 hours, it is the brightest W Ursae Majoris variable (low mass contact binary) in the night sky. Naming Nicolas Louis de Lacaille gave Epsilon Coronae Australis its Bayer designation. It is also known as HR 7152, and HD 175813. Properties Epsilon Coronae Australis is an F4V dwarf star with an effective temperature of 6000 Kelvin. It ranges between apparent magnitudes of 4.74 to 5 over 14 hours, an absolute magnitude of +2.45, and a mass of 1.1 solar masses. Epsilon Coronae Australis is a W Ursae Majoris variable A W Ursae Majoris variable, also known as a low mass contact binary, is a type of eclipsing binary variable star. These stars are close binaries of spectral types F, G, or K that share a common envelope of material and are thus in contact with one ..., indicating that it has a contact companion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Coronae Australis
Gamma Coronae Australis (γ CrA), is a binary star located in the constellation Corona Australis. The system has a combined apparent visual magnitude of 4.20, making it faintly visible to the naked eye. It is located 56.4 light-years (17.3 parsecs) from the Sun, based on its parallax. Gamma Coronae Australis is a member of the Milky Way's thin disk. The system is a visual binary, where the orbit is calculated from observations of one star orbiting the other. The primary, Gamma Coronae Australis A, is a late F-type main-sequence star with an effective temperature of 6,090 K. It has an absolute an absolute magnitude of +3.73, and a mass of 1.15 solar mass The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...es. The secondary, Gamma Coronae Australis B, is also F-type. With a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Coronae Australis
Beta Coronae Australis (Beta CrA), Latinized from β Coronae Australis, is a solitary star located in the southern constellation Corona Australis. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.10. The star is located around 470 light years distant from the Sun based on parallax, and is drifting further away with a radial velocity of . At its current distance, Beta CrA's brightness is diminished by 0.29 magnitudes due to interstellar dust. Beta CrA has a stellar classification of K0 II/III CN1.5, indicating that it is an evolved K-type star with the blended luminosity class of a bright giant and a regular giant star. The suffix ''CN1.5'' indicates that the object has an anamolous overabundance of cyano radicals in its spectrum, making it a CN star. Having exhausted the supply of hydrogen at its core, the star has expanded to 39 times the Sun's girth. It has 5.17 times the mass of the Sun shines with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta Coronae Australis
Delta Coronae Australis is a single star located in the southern constellation of Corona Australis. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.57. The star is located about 174 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +21 km/s. This object is an evolved giant star with a stellar classification of K1III. After exhausting the supply of hydrogen at its core, the star expanded off the main sequence and now has 11 times the radius of the Sun. It is a red clump giant, which indicates it is on the horizontal branch and is generating energy through core helium fusion. The star is 2.8 billion years old with 1.5 times the mass of the Sun. It is radiating 55 times the Sun's luminosity from its enlarged photosphere at an effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would em ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeta Coronae Australis
Zeta Coronae Australis (ζ Coronae Australis) is a solitary, blue-white hued star located in the southern constellation Corona Australis. With an apparent visual magnitude of +4.75, it is sufficiently bright to be viewed with the naked eye. Based upon an annual parallax shift of 16.89 mas as seen from Earth, this star is located around 193 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.15 due to interstellar dust. This is a B-type main sequence star with a stellar classification of B9.5 Vann. The suffix notation 'nn' indicates there are broad spectrum absorption lines in the spectrum associated with its rotation period. At the estimated age of just 76 million years, it is spinning rapidly with a projected rotational velocity of 308 km/s. The star has 2.92 times the mass of the Sun and 2.11 times the Sun's radius. It is radiating 51 times the Sun's luminosity from its photosphere at an e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eta1 Coronae Australis
Eta1 Coronae Australis, Latinized from η1 CrA, is a suspected astrometric binary star system in the constellation of Corona Australis. It is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.456. Parallax measurements put it at a distance of 317 light-years away from the Sun. The visible component is an A-type main-sequence star with a stellar classification of A3V, which indicates it is generating energy through core hydrogen fusion. It has broad spectrum absorption lines associated with its rotation period, having a projected rotational velocity of 122.3 km/s. The star is radiating 58 times the luminosity of the Sun from its photosphere at an 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Telescopii
Alpha Telescopii, Latinized from α Telescopii, is the brightest star in the southern constellation of Telescopium, with an apparent visual magnitude of 3.5. The ancient Roman astronomer Ptolemy included it in the constellation Corona Australis, but it was moved to Telescopium when that constellation was created by French astronomer Nicolas Louis de Lacaille in the 18th century. Parallax measurements put it at a distance of from Earth. At that range, the visual magnitude of the star is diminished by an extinction of 0.22 due to interstellar dust. Properties Physical Characteristics This star is much larger than the Sun, with an estimated times the mass and times the radius. The spectrum of the star matches a stellar classification of B3 IV, where the luminosity class of 'IV' indicates this is a subgiant star that has nearly exhausted the supply of hydrogen at its core and is evolving away from the main sequence. Alpha Telescopii is a bright star that is radia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterism (astronomy)
An asterism is an observed pattern or group of stars in the sky. Asterisms can be any identified pattern or group of stars, and therefore are a more general concept than the formally defined 88 constellations. Constellations are based on asterisms, but unlike asterisms, constellations outline and today completely divide the sky and all its celestial objects into regions around their central asterisms. For example, the asterism known as the Big Dipper comprises the seven brightest stars in the constellation Ursa Major. Another is the asterism of the Southern Cross, within the constellation of Crux. 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. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dipper (Chinese Constellation)
The Dipper mansion (斗宿, pinyin: Dǒu Xiù) is one of the Twenty-eight mansions of the Chinese constellations. It is one of the northern mansions of the Black Tortoise. In Taoism, it is known as the "Six Stars of the Southern Dipper" (南斗六星, Nándǒu liù xīng), in contrast to the Big Dipper The Big Dipper ( US, Canada) or the Plough ( UK, Ireland) is a large asterism consisting of seven bright stars of the constellation Ursa Major; six of them are of second magnitude and one, Megrez (δ), of third magnitude. Four define a "bowl" ... north to this mansion. Asterisms Stars * ζ Sgr * τ Sgr * σ Sgr * φ Sgr * λ Sgr * μ Sgr {{DEFAULTSORT:Dipper (Chinese Constellation) Chinese constellations ... [...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 accurate obser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
