|
Cassiopeia Constellation
Cassiopeia () is a constellation in the northern sky named after the vain queen Cassiopeia, mother of Andromeda, in Greek mythology, who boasted about her unrivaled beauty. Cassiopeia was one of the 48 constellations listed by the 2nd-century Greek astronomer Ptolemy, and it remains one of the 88 modern constellations today. It is easily recognizable due to its distinctive ' W' shape, formed by five bright stars. Cassiopeia is located in the northern sky and from latitudes above 34°N it is visible year-round. In the (sub)tropics it can be seen at its clearest from September to early November, and at low southern, tropical, latitudes of less than 25°S it can be seen, seasonally, low in the North. At magnitude 2.2, Alpha Cassiopeiae, or Schedar, is generally the brightest star in Cassiopeia, though it is occasionally outshone by the variable Gamma Cassiopeiae, which has reached magnitude 1.6. The constellation hosts some of the most luminous stars known, including the yell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lexico
Lexico was a dictionary website that provided a collection of English and Spanish dictionaries produced by Oxford University Press (OUP), the publishing house of the University of Oxford. While the dictionary content on Lexico came from OUP, this website was operated by Dictionary.com, whose eponymous website hosts dictionaries by other publishers such as Random House. The website was closed and redirected to Dictionary.com on 26 August 2022. Before the Lexico site was launched, the '' Oxford Dictionary of English'' and ''New Oxford American Dictionary'' were hosted by OUP's own website Oxford Dictionaries Online (ODO), later known as Oxford Living Dictionaries. The dictionaries' definitions have also appeared in Google definition search and the Dictionary application on macOS, among others, licensed through the Oxford Dictionaries API. History In the 2000s, OUP allowed access to content of the ''Compact Oxford English Dictionary of Current English'' on a website called AskOx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromeda (mythology)
In Greek mythology, Andromeda (; grc, Ἀνδρομέδα, Androméda or , ''Andromédē'') is the daughter of the king of Aethiopia, Cepheus (father of Andromeda), Cepheus, and his wife, Cassiopeia (mother of Andromeda), Cassiopeia. When Cassiopeia boasts that she is more beautiful than the Nereids, Poseidon sends the sea monster Cetus (mythology), Cetus to ravage the coast of Aethiopia as divine punishment. Andromeda is chained to a rock as a sacrifice to sate the monster, but is saved from death by Perseus, who marries her and takes her to Greece to reign as his queen. As a subject, Andromeda has been popular in art since classical times; rescued by a Greek hero cult, Greek hero, Andromeda's narration is considered the forerunner to the "princess and dragon" Motif (narrative), motif. From the Renaissance, interest revived in the original story, typically as derived from Ovid's ''Metamorphoses'' (4.663ff). Etymology Her name is the Latin, Latinized form of the Greek (''Androm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Radio Source
An astronomical radio source is an object in outer space that emits strong radio waves. Radio emission comes from a wide variety of sources. Such objects are among the most extreme and energetic physical processes in the universe. History In 1932, American physicist and radio engineer Karl Jansky detected radio waves coming from an unknown source in the center of our galaxy. Jansky was studying the origins of radio frequency interference for Bell Laboratories. He found "...a steady hiss type static of unknown origin", which eventually he concluded had an extraterrestrial origin. This was the first time that radio waves were detected from outer space. The first radio sky survey was conducted by Grote Reber and was completed in 1941. In the 1970s, some stars in our galaxy were found to be radio emitters, one of the strongest being the unique binary MWC 349. Sources: solar system The Sun As the nearest star, the Sun is the brightest radiation source in most frequencies, down to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supernova Remnant
A supernova remnant (SNR) is the structure resulting from the explosion of a star in a supernova. The supernova remnant is bounded by an expanding shock wave, and consists of ejected material expanding from the explosion, and the interstellar material it sweeps up and shocks along the way. There are two common routes to a supernova: either a massive star may run out of fuel, ceasing to generate fusion energy in its core, and collapsing inward under the force of its own gravity to form a neutron star or a black hole; or a white dwarf star may accrete material from a companion star until it reaches a critical mass and undergoes a thermonuclear explosion. In either case, the resulting supernova explosion expels much or all of the stellar material with velocities as much as 10% the speed of light (or approximately 30,000 km/s). These speeds are highly supersonic, so a strong shock wave forms ahead of the ejecta. That heats the upstream plasma up to temperatures well above mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cassiopeia A
Cassiopeia A (Cas A) () is a supernova remnant (SNR) in the constellation Cassiopeia and the brightest extrasolar radio source in the sky at frequencies above 1 GHz. The supernova occurred approximately away within the Milky Way; given the width of the Orion Arm, it lies in the next-nearest arm outwards, the Perseus Arm, about 30 degrees from the Galactic anticenter. The expanding cloud of material left over from the supernova now appears approximately across from Earth's perspective. It has been seen in wavelengths of visible light with amateur telescopes down to 234 mm (9.25 in) with filters. It is estimated that light from the supernova itself first reached Earth near the 1690s, although there are no definitively corresponding records from then. Cas A is circumpolar at and above mid-Northern latitudes which had extensive records and basic telescopes. Its likely omission in records is probably due to interstellar dust absorbing optical wavelengt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SN 1572
SN 1572 ('' Tycho's Supernova'', ''Tycho's Nova''), or B Cassiopeiae (B Cas), was a supernova of Type Ia in the constellation Cassiopeia, one of eight supernovae visible to the naked eye in historical records. It appeared in early November 1572 and was independently discovered by many individuals. Its supernova remnant has been observed optically but was first detected at radio wavelengths; it is often known as 3C 10, a radio-source designation, although increasingly as Tycho's supernova remnant. Historic description The appearance of the Milky Way supernova of 1572 belongs among the most important observation events in the history of astronomy. The appearance of the "new star" helped to revise ancient models of the heavens and to speed on a revolution in astronomy that began with the realisation of the need to produce better astrometric star catalogues (and thus the need for more precise astronomical observing instruments). It also challenged the Aristotelian dogma of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
6 Cassiopeiae
6 Cassiopeiae (6 Cas) is a white hypergiant in the constellation Cassiopeia, and a small-amplitude variable star. System 6 Cassiopeiae A is a white A2.5 type hypergiant. It is about 25 times as massive as the Sun and 200,000 times as luminous. The star is slightly and erratically variable, an Alpha Cygni variable. Not all sources consider 6 Cas to be a hypergiant. It is thought that the "+" in an early A3 Ia+ spectral classification referred to indications of additional spectral features from a possible companion rather than the more modern indication of a hypergiant luminosity class. However, later publications have given more conventional hypergiant spectral types such as B9Ia+ and A3Ia+. 6 Cas A has a number of close companions, most notably an 8th magnitude O class bright giant at only . Its spectral type is O9.75 and its absolute magnitude is −5.8. Both are considered to be members of the Cassiopeia OB5 stellar association at a distance of around 8,000 l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
V509 Cassiopeiae
V509 Cassiopeiae (V509 Cas or HR 8752) is one of two yellow hypergiant stars found in the constellation Cassiopeia, which also contains Rho Cassiopeiae. HR 8752 is around 15,700 light-years from Earth. It has an apparent magnitude that has varied from below +6 in historical times to a peak of +4.6 and now around +5.3 and is classified as a semiregular variable star of type SRd. It is undergoing strong mass loss as part of its rapid evolution and has recently passed partway through the yellow evolutionary void by ejecting around a solar mass of material in 20 years. A hot main sequence companion (B1V) was described in 1978 on the basis of a colour excess in the ultraviolet. Observations Brightness HR 8752 is a naked eye star but it has no Bayer or Flamsteed designation, and is not recorded in other catalogues before the 19th century. When first recorded in the Radcliffe Observatory catalogue in 1840 it was 6th magnitude, and it is assumed it had been 6th magnitude ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rho Cassiopeiae
Rho Cassiopeiae (; ρ Cas, ρ Cassiopeiae) is a yellow hypergiant star in the constellation Cassiopeia. It is about from Earth, yet can still be seen by the naked eye as it is over 300,000 times brighter than the Sun. On average it has an absolute magnitude of −9.5, making it visually one of the most luminous stars known. Its diameter measures between 400 and 500 times that of the Sun, approximately 627,000,000 kilometers, or about twice the size of the Earth's orbit. Rho Cassiopeiae is a single star, and is categorized as a semiregular variable. As a yellow hypergiant, it is one of the rarest types of stars. Only a few dozen are known in the Milky Way, but it is not the only one in its constellation which also contains V509 Cassiopeiae. Observation The Bayer designation for this star was established in 1603 as part of the ''Uranometria'', a star catalog produced by Johann Bayer. The star catalog by John Flamsteed published in 1712, which orders the stars in each co ... [...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] |
25th Parallel South
The 25th parallel south is a circle of latitude that is 25 degrees south of the Earth's equatorial plane, just south of the Tropic of Capricorn. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australasia, the Pacific Ocean and South America. Around the world Starting at the Prime Meridian and heading eastwards, the parallel 25° south passes through: : See also * 24th parallel south *26th parallel south The 26th parallel south latitude is a circle of latitude that is 26 degrees south of Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australia, the Pacific Ocean and South America. Around the world Starting ... {{geographical coordinates, state=collapsed s25 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
34th Parallel North
The 34th parallel north is a circle of latitude that is 34 degrees north of the Earth's equatorial plane. It crosses Africa, the Mediterranean Sea, Asia, the Pacific Ocean, North America and the Atlantic Ocean. The parallel formed the southern boundary of the original Colony of Virginia as outlined in the London Company charter. In the Confederate States, the parallel formed the northern boundary of Arizona Territory. At this latitude the sun is visible for 14 hours, 25 minutes during the summer solstice and 9 hours, 53 minutes during the winter solstice. Around the world Starting at the Prime Meridian A prime meridian is an arbitrary meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great c ... and heading eastwards, the parallel 34° north passes through: : See also * 33rd parallel north * 35th parallel north Refere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
