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Pavo (constellation)
Pavo is a constellation in the southern sky whose name is Latin for "peacock". Pavo first appeared on a 35-cm (14 in) diameter celestial globe published in 1598 in Amsterdam by Plancius and Jodocus Hondius and was depicted in Johann Bayer's star atlas '' Uranometria'' of 1603, and was likely conceived by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. French explorer and astronomer Nicolas-Louis de Lacaille gave its stars Bayer designations in 1756. The constellations Pavo, Grus, Phoenix and Tucana are collectively known as the "Southern Birds". The constellation's brightest member, Alpha Pavonis, is also known as Peacock and appears as a 1.91- magnitude blue-white star, but is actually a spectroscopic binary. Delta Pavonis is a nearby Sun-like star some 19.9 light-years distant. Six of the star systems in Pavo have been found to host planets, including HD 181433 with a super-earth, and HD 172555 with evidence of a major ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peafowl
Peafowl is a common name for three bird species in the genera '' Pavo'' and '' Afropavo'' within the tribe Pavonini of the family Phasianidae, the pheasants and their allies. Male peafowl are referred to as peacocks, and female peafowl are referred to as peahens, although peafowl of either sex are often referred to colloquially as "peacocks." The two Asiatic species are the blue or Indian peafowl originally of the Indian subcontinent, and the green peafowl of Southeast Asia; the one African species is the Congo peafowl, native only to the Congo Basin. Male peafowl are known for their piercing calls and their extravagant plumage. The latter is especially prominent in the Asiatic species, which have an eye-spotted "tail" or "train" of covert feathers, which they display as part of a courtship ritual. The functions of the elaborate iridescent colouration and large "train" of peacocks have been the subject of extensive scientific debate. Charles Darwin suggested that they ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petrus Plancius
Petrus Plancius (; 1552 – 15 May 1622) was a Dutch-Flemish astronomer, cartographer and clergyman. He was born as Pieter Platevoet in Dranouter, now in Heuvelland, West Flanders. He studied theology in Germany and England. At the age of 24 he became a minister in the Dutch Reformed Church. Plancius fled from Brussels to Amsterdam to avoid religious prosecution by the Inquisition after the city fell into Spanish hands in 1585. In Amsterdam he became interested in navigation and cartography and, having access to nautical charts recently brought from Portugal, he was soon recognized as an expert on safe maritime routes to India and the nearby "spice islands". This enabled colonies and port trade in both, including what would become the Dutch East Indies, named after the Dutch East India Company set up in 1602. He saw strong potential in the little-mapped Arctic Sea and strongly believed in the idea of a Northeast Passage until the failure of Willem Barentsz's third voyage in 159 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 181433
HD 181433 is a star located approximately 87 light-years away in the constellation of Pavo (the Peacock). According to SIMBAD, it has a stellar classification of K3III-IV, which puts it on the borderline between being a red giant and a subgiant. This is inconsistent with the fact that its luminosity is only 0.308 times that of the Sun. Its entry in the Hipparcos catalogue lists a spectral type of K5V, classifying it as a dwarf star. , three extrasolar planets are thought to be orbiting the star. There is currently little information on these planets. The name of this star comes from its identifier in the Henry Draper catalogue. Planetary system Orbiting the star are three planets, whose discovery was announced in 2008; the discovery paper was published in 2009. The inner planet has a mass at least 7.5 times that of Earth, and is termed a super-Earth (this classification is based solely on the mass of the planet and should not be taken to imply that the planet could su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star System
A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a '' star cluster'' or ''galaxy'', although, broadly speaking, they are also star systems. Star systems are not to be confused with planetary systems, which include planets and similar bodies (such as comets). A star system of two stars is known as a ''binary star'', ''binary star system'' or ''physical double star''. If there are no tidal effects, no perturbation from other forces, and no transfer of mass from one star to the other, such a system is stable, and both stars will trace out an elliptical orbit around the barycenter of the system indefinitely. ''(See Two-body problem)''. Examples of binary systems are Sirius, Procyon and Cygnus X-1, the last of which probably consists of a star and a black hole. Multiple star systems A multiple star system consists of three or more stars that appe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light-year
A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distance, astronomical distances and is equivalent to about 9.46 Orders of magnitude (numbers)#1012, trillion kilometers (), or 5.88 trillion miles ().One trillion here is long and short scales, taken to be 1012 (one million million, or billion in long scale). As defined by the International Astronomical Union (IAU), a light-year is the distance that Speed of light, light travels in a vacuum in one Julian year (astronomy), Julian year (365.25 days). Because it includes the time-measurement word "year", the term ''light-year'' is sometimes misinterpreted as a unit of time. The ''light-year'' is most often used when expressing distances to stars and other distances on a Galaxy, galactic scale, especially in public understanding of science, non-specialist contexts and popular science publications. The unit most commonly used in professional astronomy is the parsec (symbol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta Pavonis
Delta Pavonis, Latinized from δ Pavonis, is a single star in the southern constellation of Pavo. It has an apparent visual magnitude of 3.56, making it a fourth-magnitude star that is visible to the naked eye from the southern hemisphere. Parallax measurements yield an estimated distance of from Earth. This makes it one of the nearest bright stars to the Solar System. It is approaching the Sun with a radial velocity of −23.5 km/s, and is predicted to come as close as in around 49,200 years. Observations This object is a subgiant of spectral type G8 IV; it will stop fusing hydrogen at its core relatively soon, starting the process of becoming a red giant. Hence, Delta Pavonis is 24% brighter than the Sun, but the effective temperature of its outer atmosphere is less: 5,571 K. Its mass is 105% of Sol's mass, with a mean radius 120% of Sol's radius. Delta Pavonis's surface convection zone extends downward to about 43.1% of the star's radius, bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectroscopic Binary
A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in which case they are called ''visual binaries''. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (''spectroscopic binaries'') or astrometry (''astrometric binaries''). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit each other; these pairs are called ''eclipsing binaries'', or, together with other binaries that change brightness as they orbit, ''photometric binaries''. If components in binary star systems are close enough they can gravitationally distort their mutual outer stellar atmospheres. In some cases, the ... [...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] |
Tucana
Tucana (The Toucan) is a constellation of stars in the southern sky, named after the toucan, a South American bird. It is one of twelve constellations conceived in the late sixteenth century by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. Tucana 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 its stars Bayer designations in 1756. The constellations Tucana, Grus, Phoenix and Pavo are collectively known as the "Southern Birds". Tucana is not a prominent constellation as all of its stars are third magnitude or fainter; the brightest is Alpha Tucanae with an apparent visual magnitude of 2.87. Beta Tucanae is a star system with six member stars, while Kappa is a quadruple system. Five star systems have been found to have exoplanets to date. The const ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phoenix (constellation)
Phoenix is a minor constellation in the southern sky. Named after the mythical Phoenix (mythology), phoenix, it was first depicted on a celestial atlas by Johann Bayer in his 1603 ''Uranometria''. The French explorer and astronomer Nicolas Louis de Lacaille charted the brighter stars and gave their Bayer designations in 1756. The constellation stretches from roughly −39° to −57° declination, and from 23.5h to 2.5h of right ascension. The constellations Phoenix, Grus (constellation), Grus, Pavo (constellation), Pavo and Tucana, are known as the Southern Birds. The brightest star, Alpha Phoenicis, is named Ankaa, an Arabic word meaning 'the Phoenix'. It is an orange giant of apparent magnitude 2.4. Next is Beta Phoenicis, actually a Binary star, binary system composed of two yellow giants with a combined apparent magnitude of 3.3. Nu Phoenicis has a dust disk, while the constellation has ten star systems with known planets and the recently discovered galaxy clusters El Gord ... [...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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayer Designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. The brighter stars were assigned their first systematic names by the German astronomer Johann Bayer in 1603, in his star atlas '' Uranometria''. Bayer catalogued only a few stars too far south to be seen from Germany, but later astronomers (including Nicolas-Louis de Lacaille and Benjamin Apthorp Gould) supplemented Bayer's catalog with entries for southern constellations. Scheme Bayer assigned a lowercase Greek letter (alpha (α), beta (β), gamma (γ), etc.) or a Latin letter (A, b, c, etc.) to each star he catalogued, combined with the Latin name of the star's parent constellation in genitive (possessive) form. The constellation name is frequently abbreviated to a standard three-letter form. For example, Aldebaran in the constellat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
