|
Alnair
Alpha Gruis is the brightest star in the southern constellation of Grus. It is officially named Alnair; ''Alpha Gruis'' is the star's Bayer designation, which is Latinized from α Gruis and abbreviated α Gru. With an magnitude of 1.7, it is one of the brightest stars in the sky and one of the fifty-eight stars selected for celestial navigation. Alpha Gruis is a single, B-type main-sequence star located at a distance of . Nomenclature ''α Gruis'' ( Latinised to ''Alpha Gruis'') is the star's Bayer designation. (Its first depiction in a celestial atlas was in Johann Bayer's ''Uranometria'' of 1603.) It bore the traditional name ''Alnair'' or ''Al Nair'' (sometimes ''Al Na'ir'' in lists of stars used by navigators), from the Arabic ''al-nayyir'' "the bright one", itself derived from its Arabic name, ''al-nayyir min dhanab al-ḥūt (al-janūbiyy)'', "the bright one from the (southern) fish's tail" (see Aldhanab). Confusingly, ''Alnair'' was also given as the prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grus (constellation)
Grus (, or colloquially ) is a constellation in the southern sky. Its name is Latin for the crane, a type of bird. It is one of twelve constellations conceived by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. Grus first appeared on a celestial globe published in 1598 in Amsterdam by Plancius and Jodocus Hondius and was depicted in Johann Bayer's star atlas ''Uranometria'' of 1603. French explorer and astronomer Nicolas-Louis de Lacaille gave Bayer designations to its stars in 1756, some of which had been previously considered part of the neighbouring constellation Piscis Austrinus. The constellations Grus, Pavo, Phoenix and Tucana are collectively known as the "Southern Birds". The constellation's brightest star, Alpha Gruis, is also known as Alnair and appears as a 1.7-magnitude blue-white star. Beta Gruis is a red giant variable star with a minimum magnitude of 2.3 and a maximum magnitude of 2.0. Six star systems have been foun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeta Centauri
Zeta Centauri, Latinized from ζ Centauri, is a binary star system in the southern constellation of Centaurus. It has the proper name Alnair , from the Arabic ''Nayyir Baṭan Qanṭūris'' (نير بطن قنطورس), meaning "The Bright (Star) of the Body of the Centaur". With a combined apparent visual magnitude of +2.55, it is one of the brighter members of the constellation. This system is close enough to the Earth that its distance can be measured directly using the parallax technique. This yields a value of roughly , with a 1.6% margin of error. It is drifting further away with a radial velocity of +6.5 km/s. In Chinese, (), meaning ''Arsenal'', refers to an asterism consisting of ζ Centauri, η Centauri, θ Centauri, 2 Centauri, HD 117440, ξ1 Centauri, γ Centauri, τ Centauri, D Centauri and σ Centauri. Consequently, the Chinese name for ζ Centauri itself is (, en, the First Star of Arsenal.) ζ Cen is a double-lined spectroscopic binary syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Brightest Stars
This is a list of stars arranged by their apparent magnitude – their brightness as observed from Earth. It includes all stars brighter than magnitude +2.50 in visible light, measured using a ''V''-band filter in the UBV photometric system. Stars in binary systems (or other multiples) are listed by their ''total'' or ''combined'' brightness if they appear as a single star to the naked eye, or listed separately if they do not. As with all magnitude systems in astronomy, the scale is logarithmic and inverted i.e. lower/more negative numbers are brighter. Most stars on this list appear bright from Earth because they are nearby, not because they are intrinsically luminous. For a list which compensates for the distances, converting the ''apparent'' magnitude to the ''absolute'' magnitude, see the list of most luminous stars. Measurement The Sun is the brightest star as viewed from Earth, at −26.74 mag. The second brightest is Sirius at −1.46 mag. For compa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the earliest constellations likely go back to prehistory. People used them to relate stories of their beliefs, experiences, creation, or mythology. Different cultures and countries adopted their own constellations, some of which lasted into the early 20th century before today's constellations were internationally recognized. The recognition of constellations has changed significantly over time. Many changed in size or shape. Some became popular, only to drop into obscurity. Some were limited to a single culture or nation. The 48 traditional Western constellations are Greek. They are given in Aratus' work ''Phenomena'' and Ptolemy's ''Almagest'', though their origin probably predates these works by several centuries. Constellations in the far southern sky were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and development through global cooperation. It was founded in 1919 and is based in Paris, France. The IAU is composed of individual members, who include both professional astronomers and junior scientists, and national members, such as professional associations, national societies, or academic institutions. Individual members are organised into divisions, committees, and working groups centered on particular subdisciplines, subjects, or initiatives. As of 2018, the Union had over 13,700 individual members, spanning 90 countries, and 82 national members. Among the key activities of the IAU is serving as a forum for scientific conferences. It sponsors nine annual symposia and holds a triannual General Assembly that sets policy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epsilon Gruis
ε Gruis, Latinised as Epsilon Gruis, is a blue-white hued star in the southern constellation of Grus. It is visible to the naked eye, having an apparent visual magnitude of 3.5. Based upon an annual parallax shift of 25.30 mas as measured from Earth, it is located around 129 light years from the Sun. The system may be moving closer to the Sun with a radial velocity of about −0.4 km/s. This is an A-type subgiant of spectral type A2IVn, a star that has used up its core hydrogen and has begun to expand off the main sequence. At the estimated age of 249 million years, it is spinning rapidly with a projected rotational velocity of 235 km/s. This is giving the star an oblate shape with an equatorial bulge that is an estimated 18% larger than the polar radius. The star displays an infrared excess, suggesting the presence of a circumstellar disk A circumstellar disc (or circumstellar disk) is a torus, pancake or ring-shaped accretion disk of mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta2 Gruis
Delta2 Gruis, Latinized from δ2 Gruis, is a solitary, red-hued star in the southern constellation of Grus. It is visible to the naked eye with an apparent visual magnitude of about 4. Based upon an annual parallax shift of 9.88 mas as seen from the Earth, the star is located around 330 light years from the Sun. It is moving further away from the Sun with a radial velocity of +3 km/s. This is an evolved red giant star with a stellar classification of M4.5 IIIa. It is a pulsating variable with multiple periods, including 20.6, 24.1, 24.5, and 32.3 days. The strongest period is 33.3 days with an amplitude of 0.043 magnitude. It has a magnitude 9.71 visual companion at an angular separation of 60.4 arc seconds along a position angle In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the north celestial pole ( ... [...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] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arabian Astronomy
Islamic astronomy comprises the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age (9th–13th centuries), and mostly written in the Arabic language. These developments mostly took place in the Middle East, Central Asia, Al-Andalus, and North Africa, and later in the Far East and India. It closely parallels the genesis of other Islamic sciences in its assimilation of foreign material and the amalgamation of the disparate elements of that material to create a science with Islamic characteristics. These included Greek, Sassanid, and Indian works in particular, which were translated and built upon. Islamic astronomy played a significant role in the revival of Byzantine and EuropeanSaliba (1999). astronomy following the loss of knowledge during the early medieval period, notably with the production of Latin translations of Arabic works during the 12th century. Islamic astronomy also had an influence on Chinese astronomy and Malian a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambda Gruis
Lambda Gruis, Latinized from λ Gruis, is a solitary, orange-hued star in the southern constellation of Grus. With an apparent visual magnitude of 4.47, it is visible to the naked eye as a faint point of light. The distance to this star, as determined using an annual parallax shift of 13.47 mas as seen from the Earth, is around 242 light years. It is drifting further away with a radial velocity of +39 km/s, having come to within some 805,000 years ago. This is an evolved K-type giant star with a stellar classification of K3 III, having exhausted the supply of hydrogen at its core then cooled and expanded off the main sequence. It has about 2.4 times the mass of the Sun and has expanded to 22.3 times the Sun's radius. The star is radiating 155 times the Sun's luminosity 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
