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Epsilon Apodis
Epsilon Apodis, Latinized from ε Apodis, is the Bayer designation for a star in the southern circumpolar constellation of Apus. It has an apparent visual magnitude of 5.06, which is bright enough to be viewed from dark suburban skies. Based upon parallax measurements, it is at a distance of roughly from Earth. Based upon a stellar classification of B3 V, this is a massive, B-type main sequence star that is generating energy through the fusion of hydrogen at its core. Epsilon Apodis has more than six times the mass of the Sun and nearly four times the Sun's radius. It is radiating 1,614 times as much luminosity as the Sun from its outer envelope at an effective temperature of 17,050 K. At this heat, it has a blue-white glow that is a characteristic of B-type stars. It is spinning rapidly, with a projected rotational velocity of 255 km/s giving a lower bound for the azimuthal velocity along the equator. Epsilon Apodis is classified as a Gamma Cass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apus
Apus is a small constellation in the Southern Celestial Hemisphere, southern sky. It represents a bird-of-paradise, and its name means "without feet" in Greek language, Greek because the bird-of-paradise was once wrongly believed to lack feet. First depicted on a celestial globe by Petrus Plancius in 1598, it was charted on a star atlas by Johann Bayer in his 1603 ''Uranometria''. The French explorer and astronomer Nicolas Louis de Lacaille charted and gave the brighter stars their Bayer designations in 1756. The five brightest stars are all reddish in hue. Shading the others at apparent magnitude 3.8 is Alpha Apodis, an orange giant that has around 48 times the diameter and 928 times the luminosity of the Sun. Marginally fainter is Gamma Apodis, another ageing giant star. Delta Apodis is a double star, the two components of which are 103 Minute and second of arc, arcseconds apart and visible with the naked eye. Two star systems have been found to have exoplanet, planets. Hist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Atmosphere
The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone. Overview The stellar atmosphere is divided into several regions of distinct character: * The photosphere, which is the atmosphere's lowest and coolest layer, is normally its only visible part. Light escaping from the surface of the star stems from this region and passes through the higher layers. The Sun's photosphere has a temperature in the 5,770 K to 5,780 K range. Starspots, cool regions of disrupted magnetic field lie on the photosphere. * Above the photosphere lies the chromosphere. This part of the atmosphere first cools down and then starts to heat up to about 10 times the temperature of the photosphere. * Above the chromosphere lies the transition region, where the temperature increases rapidly on a distance of only around 100 km. * The outermost part of the stellar atmosphere is the corona, a tenuous plasma which has a tem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta Octantis
δ Octantis, Latinised as Delta Octantis, has the distinction of being Saturn's southern pole star. An orange giant of class K2III, it has 1.2 times the mass of the Sun and about 25 times the Sun's radius. This star is about 4.3 billion years old, which is similar to the age of the Sun. Naming In Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ... caused by adaptation of the European southern hemisphere constellations into the Chinese system, (), meaning '' Exotic Bird'', refers to an asterism consisting of δ Octantis, ζ Apodis, ι Apodis, β Apodis, γ Apodis, δ1 Apodis, η Apodis, α Apodis and ε Apodis. Consequently, δ Octantis itself is known as (, en, the Fifth Star of Exotic Bird). References Octans Octantis, Delta CD-83 189 070638 5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Apodis
Gamma Apodis (γ Aps, γ Apodis) is the Bayer designation for a star in the southern circumpolar constellation of Apus. From parallax measurements, the distance to this star can be estimated as . It is visible to the naked eye with an apparent visual magnitude of 3.86. A stellar classification of G9 III identifies it as a giant star in the later stages of its evolution. It is an active X-ray source with a luminosity of , making it one of the 100 strongest stellar X-ray sources within 50 parsecs of the Sun. Naming In Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ... caused by adaptation of the European southern hemisphere constellations into the Chinese system, (), meaning '' Exotic Bird'', refers to an asterism consisting of γ Apodis, ζ Apodis, ι Apo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Apodis
Beta Apodis (β Aps, β Apodis) is the Bayer designation for a star in the southern circumpolar constellation of Apus. It is located approximately from Earth, as determined by parallax measurements. The apparent visual magnitude of this star is +4.24, which is bright enough to be seen with the naked eye The spectrum of this star matches the characteristics of a K0 III, which, according to models of stellar evolution, indicates that it is in the giant star stage, having exhausted the supply of hydrogen at its core. The measured angular diameter of this star is . At the estimated distance of this star, this yields a physical size of about 11 times the radius of the Sun. The expanded outer atmosphere of Beta Apodis has an effective temperature of about 4,900 K. This heat is causing it to glow with the characteristic orange hue of a K-type star. Naming In Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese natio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iota Apodis
Iota Apodis (ι Aps, ι Apodis) is the Bayer designation for a binary star system in the southern circumpolar constellation of Apus. It is a faint target at an apparent visual magnitude of 5.41, but still visible to the naked eye from suitably dark skies. The distance to this star can be roughly gauged from parallax measurements, yielding an estimate of with a 20% margin of error. Both stars are B-type main sequence stars, which indicates they shine with a blue-white hue. The brighter component has a stellar classification of B9 V and an apparent magnitude 5.90, while the second member is a B9.5 V star with a magnitude of 6.46. The pair have an angular separation of 0.091 arcseconds with an estimated orbital period of 59.32 years. They are about 3.89 and 3.45 times as massive as the Sun. Naming In Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeta Apodis
Zeta Apodis, Latinized from ζ Apodis, is the Bayer designation for a star in the southern constellation of Apus. It has an apparent visual magnitude of +4.78, which is bright enough to allow it to be seen with the naked eye. The distance to this star is known from parallax measurements to be around . The spectrum of Zeta Apodis matches a stellar classification of K2 III, with the luminosity class of III indicating it is an evolved giant star. The measured angular diameter of this star, after correction for limb darkening, is . At the estimated distance of Eta Draconis, this yields a physical size of about 11 times the radius of the Sun. The outer atmosphere has an effective temperature of 4,388 K, which gives it the orange-hued glow of a K-type star. Naming In Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Constellations
Traditional Chinese astronomy has a system of dividing the celestial sphere into asterisms or constellations, known as "officials" (Chinese ''xīng guān''). The Chinese asterisms are generally smaller than the constellations of Hellenistic tradition. The Song dynasty (13th-century) Suzhou planisphere shows a total of 283 asterisms, comprising a total of 1,565 individual stars. The asterisms are divided into four groups, the Twenty-Eight Mansions (, ''Èrshíbā Xiù'') along the ecliptic, and the Three Enclosures of the northern sky. The southern sky was added as a fifth group in the late Ming Dynasty based on European star charts, comprising an additional 23 asterisms. The Three Enclosures (, ''Sān Yuán'') include the Purple Forbidden Enclosure, which is centered on the north celestial pole and includes those stars which could be seen year-round,Needham, J.Astronomy in Ancient and Medieval China. ''Philosophical Transactions of the Royal Society of London''. Series A, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Language
Chinese (, especially when referring to written Chinese) is a group of languages spoken natively by the ethnic Han Chinese majority and many minority ethnic groups in Greater China. About 1.3 billion people (or approximately 16% of the world's population) speak a variety of Chinese as their first language. Chinese languages form the Sinitic branch of the Sino-Tibetan languages family. The spoken varieties of Chinese are usually considered by native speakers to be variants of a single language. However, their lack of mutual intelligibility means they are sometimes considered separate languages in a family. Investigation of the historical relationships among the varieties of Chinese is ongoing. Currently, most classifications posit 7 to 13 main regional groups based on phonetic developments from Middle Chinese, of which the most spoken by far is Mandarin (with about 800 million speakers, or 66%), followed by Min (75 million, e.g. Southern Min), Wu (74 million, e.g. Shangh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Star
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either: * Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks. * Extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes eclipses it. Many, possibly most, stars have at least some variation in luminosity: the energy output of the Sun, for example, varies by about 0.1% over an 11-year solar cycle. Discovery An ancient Egyptian calendar of lucky and unlucky days composed some 3,200 years ago may be the oldest preserved historical document of the discovery of a variable star, the eclipsing binary Algol. Of the modern astronomers, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Cassiopeiae Variable
A Gamma Cassiopeiae variable (γ Cassiopeiae variable) is a type of variable star, named for its prototype γ Cassiopeiae. Variability γ Cassiopeiae variables show irregular changes in brightness on a timescale of decades. These typically have amplitudes of the order of a magnitude. For example, γ Cassiopeiae is usually about magnitude 2.5 and has varied between magnitudes 1.6 and 3.0. The variations are associated with changes in the spectrum between normal absorption spectra and Be star spectra, often also including shell star characteristics. Pleione and γ Cassiopeiae itself are both variable stars that have intermittent shell episodes where strong shell features appear in the spectrum and the brightness increases or decreases significantly. At other times the shell is not detectable in the spectrum, and even the emission lines may disappear. The General Catalogue of Variable Stars (GCVS) categorises γ Cassiopeiae stars as eruptive variables and describes them as r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azimuth
An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north. Mathematically, the relative position vector from an observer (origin) to a point of interest is projected perpendicularly onto a reference plane (the horizontal plane); the angle between the projected vector and a reference vector on the reference plane is called the azimuth. When used as a celestial coordinate, the azimuth is the horizontal direction of a star or other astronomical object in the sky. The star is the point of interest, the reference plane is the local area (e.g. a circular area with a 5 km radius at sea level) around an observer on Earth's surface, and the reference vector points to true north. The azimuth is the angle between the north vector and the star's vector on the horizontal plane. Azimuth is usually measured in d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
