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Antlia Strand
Antlia (; from Ancient Greek ''ἀντλία'') is a constellation in the Southern Celestial Hemisphere. Its name means "pump" in Latin and Greek; it represents an air pump. Originally Antlia Pneumatica, the constellation was established by Nicolas-Louis de Lacaille in the 18th century. Its non-specific (single-word) name, already in limited use, was preferred by John Herschel then welcomed by the astronomic community which officially accepted this. North of stars forming some of the sails of the ship Argo Navis (the constellation Vela), Antlia is completely visible from latitudes south of 49 degrees north. Antlia is a faint constellation; its brightest star is Alpha Antliae, an orange giant that is a suspected variable star, ranging between apparent magnitudes 4.22 and 4.29. S Antliae is an eclipsing binary star system, changing in brightness as one star passes in front of the other. Sharing a common envelope, the stars are so close they will one day merge to form a single st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
La Caille Family
Constellation families are collections of constellations sharing some defining characteristic, such as proximity on the celestial sphere, common historical origin, or common mythological theme. In the Western tradition, most of the northern constellations stem from Ptolemy's list in the ''Almagest'' (which in turn has roots that go back to Mesopotamian astronomy), and most of the far southern constellations were introduced by sailors and astronomers who traveled to the south in the 16th to 18th centuries. Separate traditions arose in India and China. Menzel's families Donald H. Menzel, director of the Harvard Observatory, gathered several traditional groups in his popular account, ''A Field Guide to the Stars and Planets'' (1975), and adjusted and regularized them so that his handful of groups covered all 88 of the modern constellations. Of these families, one (Zodiac) straddles the ecliptic which divides the sky into north and south; one (Hercules) has nearly equal por ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Herschel
Sir John Frederick William Herschel, 1st Baronet (; 7 March 1792 – 11 May 1871) was an English polymath active as a mathematician, astronomer, chemist, inventor and experimental photographer who invented the blueprint and did botanical work. Herschel originated the use of the Julian day system in astronomy. He named seven moons of Saturn and four moons of Uranus – the seventh planet, discovered by his father Sir William Herschel. He made many contributions to the science of photography, and investigated colour blindness and the chemical power of ultraviolet rays. His ''Preliminary Discourse'' (1831), which advocated an Inductive reasoning, inductive approach to scientific experiment and theory-building, was an important contribution to the philosophy of science. Early life and work on astronomy Herschel was born in Slough, Buckinghamshire, the son of Mary Baldwin and astronomer Sir William Herschel. He was the nephew of astronomer Caroline Herschel. He studied short ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antlia Dwarf
The Antlia Dwarf is a dwarf spheroidal/irregular galaxy. It lies about 1.3 Mpc (4.3 million light-years) from Earth in the constellation Antlia. It is the fourth and faintest member of the nearby Antlia-Sextans Group of galaxies. The galaxy contains stars of all ages, contains significant amounts of gas, and has experienced recent star formation. The Antlia Dwarf is believed to be tidally interacting with the small barred spiral galaxy NGC 3109. Discovery The Antlia Dwarf was first cataloged in 1985 by H. Corwin, Gérard de Vaucouleurs, and A. de Vaucouleurs. Later in 1985 and 1987, it was noted as a possible nearby dwarf galaxy by two groups of astronomers. It was finally confirmed as a dwarf galaxy in 1997 by Alan Whiting, Mike Irwin and George Hau during a survey of the northern sky. They for the first time resolved it into stars and determined the distance to it—1.15 Mpc (the modern distance estimate is slightly larger). The same year, Antonio Aparicio, Jul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiral Galaxy
Spiral galaxies form a galaxy morphological classification, class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''Alt URL pp. 124–151) and, as such, form part of the Hubble sequence. Most spiral galaxies consist of a flat, rotating Disc (galaxy), disk containing stars, Interstellar medium, gas and dust, and a central concentration of stars known as the Bulge (astronomy), bulge. These are often surrounded by a much fainter Galactic halo, halo of stars, many of which reside in globular clusters. Spiral galaxies are named by their spiral structures that extend from the center into the galactic disc. The spiral arms are sites of ongoing star formation and are brighter than the surrounding disc because of the young, hot OB stars that inhabit them. Roughly two-thirds of all spirals are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 2997
NGC 2997 is a face-on unbarred spiral galaxy about 40 million light-years away in the faint southern constellation of Antlia. It was discovered March 4, 1793 by German-born astronomer William Herschel. J. L. E. Dreyer described it as, "a remarkable object, very faint, very large, very gradually then very suddenly bright middle and 4 arcsec nucleus. This is the brightest galaxy of the NGC 2997 group of galaxies, and was featured on the cover of the first edition of ''Galactic Dynamics'' by James Binney and Scott Tremaine. This is a grand-design galaxy with a symmetrical, two-armed form. The morphological classification of NGC 2997 is SAB(rs)c, indicating a weakly-barred spiral galaxy (SAB) with an incomplete ring around the bar (rs) and loosely-wound spiral arms (c). It is inclined at an angle of 40° to the line of sight from the Earth, with the major axis aligned along a position angle of 110°. The arms host a series of dusty knots that are star-forming regions being ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WASP-66
WASP-66, also known as TYC 7193-1804-1, is an F-type star in the constellation Antlia. It has an apparent magnitude of 11.6, which is much too faint to be seen with the unaided eye and is located at a distance of . WASP-66 has a classification of F4, which states that it is an ordinary F-type main sequence star that is fusing hydrogen at its core. At present it has 130% the mass of the Sun and 175 the radius of the Sun. It has an effective temperature of , which gives it a yellowish-white hue. The star is younger than Sun at billion years, and may be either metal-poor or similar to Sun in concentration of heavy elements. Currently it is spinning moderately with a projected rotational velocity of 13.4 km/s. According to a survey published in 2017, WASP-66 has one suspected companion - a red dwarf star with an effective temperature of and a projected separation of . Planetary system In 2012, a superjovian planet around WASP-66 was discovered. WASP-66b has a mass that is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 93083
HD 93083 is an orange-hued star in the southern constellation of Antlia. It has the proper name Macondo, after the mythical village of the novel One Hundred Years of Solitude (Cien años de soledad). The name was selected by Colombia during the IAU The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...'s NameExoWorlds campaign. The star has an apparent visual magnitude of 8.30, which is too faint to be visible to the naked eye. It is located at a distance of 93 light-years from the Sun based on stellar parallax, parallax. HD 93083 is drifting further away with a radial velocity of +43.65 km/s, having come to within some 484,000 years ago. This is a K-type main-sequence star that has been assigned a stellar classification of K2IV-V or K3V, depending on the study. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Envelope
In astronomy, a common envelope (CE) is gas that contains a binary star system. The gas does not rotate at the same rate as the embedded binary system. A system with such a configuration is said to be in a common envelope phase or undergoing common envelope evolution. During a common envelope phase the embedded binary system is subject to drag forces from the envelope which cause the separation of the two stars to decrease. The phase ends either when the envelope is ejected to leave the binary system with much smaller orbital separation, or when the two stars become sufficiently close to merge and form a single star. A common envelope phase is short-lived relative to the lifetime of the stars involved. Evolution through a common envelope phase with ejection of the envelope can lead to the formation of a binary system composed of a compact object with a close companion. Cataclysmic variables, X-ray binaries and systems of close double white dwarfs or neutron stars are examples of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binary Star
A binary star or binary star system 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 as separate stars using a telescope, 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 each other's outer stellar atmospheres. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S Antliae
S Antliae is a W Ursae Majoris-type eclipsing binary star in Antlia. Characteristics S Antiliae is classed as an A-type W Ursae Majoris variable, since the primary is hotter than the secondary and the drop in magnitude is caused by the latter passing in front of the former. S Antiliae varies in apparent magnitude from 6.27 to 6.83 over a period of 15.6 hours. The system shines with a combined spectrum of A9V. The system's orbital period is about 0.591 days. The stars' centres are an average of 3.82 times the Sun's radius apart. The system will evolve into an Algol variable. Calculating the properties of the component stars indicates that the primary star has a mass 1.66 times and a diameter 2.09 times that of the Sun, and the secondary has a mass 0.55 times and a diameter 1.31 times that of the Sun. The primary has a surface temperature of 7,100K, while the secondary is a little cooler at 6,859K. The two stars have similar luminosity and spectral type as they have a co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), extinction of the object's light caused by interstellar dust along the sightline, line of sight to the observer. Unless stated otherwise, the word ''magnitude'' in astronomy usually refers to a celestial object's apparent magnitude. The magnitude scale likely dates to before the ancient Ancient Greek astronomy#Astronomy in the Greco-Roman and Late Antique eras, Roman astronomer Ptolemy, Claudius Ptolemy, whose Star catalogue, star catalog popularized the system by listing stars from First-magnitude star, 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined to closely match this historical system by Norman Robert Pogson, Norman Pogson in 1856. The scale is reverse logarithmic scale, logarithmic: ... [...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 systematically 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 periodically; for example, because the star 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 exhibit at least some oscillation 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. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
