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NGC 4298
NGC 4298 is a flocculent spiral galaxy located about 53 million light-years away in the constellation Coma Berenices. The galaxy was discovered by astronomer William Herschel on April 8, 1784 and is a member of the Virgo Cluster. NGC 4298 may harbor an intermediate-mass black hole with an estimated mass ranging from 20,000 ( M☉) to 500,000 ( M☉) solar masses. Interaction with NGC 4302 NGC 4298 appears to form a pair with and appears to interact with NGC 4302. Evidence for an interaction between the two galaxies are that NGC 4298 exhibits a lopsided, asymmetrical distribution of stars, a tidal bridge that connects it to NGC 4302, a prodigious rate of star formation and an HI-tail. However, the tail is also the result of ram pressure. The two galaxies are separated from a projected distance of ~. Ram-pressure stripping The presence of a truncated gas disc, an asymmetric 6 cm polarized radio continuum distribution, an HI-tail, and asymmetries of gas in a similar dire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New General Catalogue
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxy, galaxies, star clusters and emission nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the ''Index Catalogues'' (abbreviated IC), describing a further 5,386 astronomical objects. Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use. The NGC expanded and consolidated the cataloguing work of William Herschel, William and Caroline Herschel, and John Herschel's ''General Catalogue of Nebulae and Clusters of Stars''. Objects south of the Celestial sphere, celestial equator are catalogued somewhat less thoroughly, but many were included based on observation by John Herschel or James Dunlop. The NGC contained multiple errors, but attempts to eliminate them were made by the ''Revised New Ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Masses
The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. More precisely, the mass of the Sun is The solar mass is about times the mass of Earth (), or times the mass of Jupiter (). History of measurement The value of the gravitational constant was first derived from measurements that were made by Henry Cavendish in 1798 with a torsion balance. The value he obtained differs by only 1% from the modern value, but was not as precise. The diurnal parallax of the Sun was accurately measured during the transits of Venus in 1761 and 1769, yielding a value of (9 arcseconds, compared to the present value of ). From the value of the diurnal parallax, one can determine the distance to the Sun from the geometry of Earth. The first known estimate of the solar mass was by Isaa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flocculent Spiral Galaxies
A flocculent spiral galaxy is a type of spiral galaxy. Unlike the well-defined spiral architecture of a grand design spiral galaxy, wikt:flocculent, flocculent (meaning "flaky") galaxies are patchy, with discontinuous spiral arms. SSPSF model, Self-propagating star formation is the apparent explanation for the structure of flocculent spirals. Approximately 30% of spirals are flocculent, 10% are grand design, and the rest are referred to as "multi-armed". The multiple-arm type is sometimes grouped into the flocculent category.University of Virginia, Mark Whittle, ''ASTR 553/554 : Extragalactic Astronomy (2007)''"Lecture 5: Spiral Galaxies" (Retrieved 23 April 2010). The prototypical flocculent spiral is NGC 2841."A Near-Infrared Atlas of Spiral Galaxies", Debra Meloy Elmegreen"CH3. Discussion"(Retrieved 23 April 2010) List of flocculent spiral galaxies References Sources PDF''A Near-Infrared Atlas of Spiral Galaxies'', Debra Meloy Elmegreen, 1981, , External links * COSMOS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Objects Discovered In 1784
Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, meteoroids, asteroids, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Egyptians, Babylonians, Greeks, Indians, Chinese, Maya, and many ancient indigenous peoples of the Americas. In the past, astronomy included disciplines as diverse as astrometry, celestial navigation, observational ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Principal Galaxies Catalogue Objects
Principal may refer to: Title or rank * Principal (academia), the chief executive of a university ** Principal (education), the head of a school * Principal (civil service) or principal officer, the senior management level in the UK Civil Service * Principal dancer, the top rank in ballet * Principal (music), the top rank in an orchestra Law * Principal (commercial law), the person who authorizes an agent ** Principal (architecture), licensed professional(s) with ownership of the firm * Principal (criminal law), the primary actor in a criminal offense * Principal (Catholic Church), an honorific used in the See of Lisbon Places * Principal, Cape Verde, a village * Principal, Ecuador, a parish Media * ''The Principal'' (TV series), a 2015 Australian drama series * ''The Principal'', a 1987 action film * Principal (music), the lead musician in a section of an orchestra * Principal photography, the first phase of movie production * "The Principal", a song on the album ''K- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UGC Objects
UGC may refer to: Organisations * Canadian Geophysical Union, official abbreviation in French (Union géophysique canadienne) * UGC (cinema operator), a European cinema chain, formerly Union Générale Cinématographique * UGC Fox Distribution, a former French-American film production company formed in 1995 * Union Graduate College, Schenectady, New York * United Grain Company, a Russian grain trading company based in Moscow * University Grants Commission (other) * University Grants Committee (other) * UnitedGlobalCom, former name of the cable TV operator Liberty Global * UnderGround Crips, an African American street gang mainly from Los Angeles, California Science and technology * Universal gravitational constant G, in physics * Uppsala General Catalogue, an astronomical catalogue of galaxies * UGC, a codon for cysteine * Unique games conjecture, a conjecture in computational complexity Other * User-generated content User-generated content (UGC), a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC Objects
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and emission nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the ''Index Catalogues'' (abbreviated IC), describing a further 5,386 astronomical objects. Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use. The NGC expanded and consolidated the cataloguing work of William and Caroline Herschel, and John Herschel's '' General Catalogue of Nebulae and Clusters of Stars''. Objects south of the celestial equator are catalogued somewhat less thoroughly, but many were included based on observation by John Herschel or James Dunlop. The NGC contained multiple errors, but attempts to eliminate them were made by the ''Revised New General Catalogue'' (RNGC) by Jack W. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of NGC Objects (4001–5000)
This is a list of NGC objects 4001–5000 from the New General Catalogue (NGC). The astronomical catalogue is composed mainly of star clusters, nebulae, and galaxies. Other objects in the catalogue can be found in the other subpages of the list of NGC objects. The constellation information in these tables is taken from ''The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by Jjiko. L. E. Dreyer'', which was accessed using the "VizieR Service". Galaxy types are identified using the ''NASA/IPAC Extragalactic Database''. The other data in these tables are from the SIMBAD Astronomical Database unless otherwise stated. 4001–4100 4101–4200 4201-4300 4301–4400 4401–4500 4501–4600 4601–4700 4701–4800 4801–4900 4901–5000 See also * Lists of astronomical objects This is a list of lists, grouped by type of astronomical object. Solar System * List of Solar System objects * List of gravitation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ram Pressure
Ram pressure is a pressure exerted on a body moving through a fluid medium, caused by relative bulk motion of the fluid rather than random thermal motion. It causes a drag (physics), drag force to be exerted on the body. Ram pressure is given in tensor form as :P_\text= \rho u_i u_j, where \rho is the density of the fluid; P_\text is the momentum flux per second in the i direction through a surface with normal in the j direction. u_i,u_j are the components of the fluid velocity in these directions. The total Cauchy stress tensor \sigma_ is the sum of this ram pressure and the isotropic thermal pressure (in the absence of viscosity). In the simple case when the relative velocity is normal to the surface, and momentum is fully transferred to the object, the ram pressure becomes :P_\text = 1/2 \rho u^2. Derivation The Lagrangian and Eulerian specification of the flow field, Eulerian form of the Cauchy momentum equation for a fluid is :\rho\frac = -\vec \nabla p - \rho(\vec u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star Formation
Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"—Jeans instability, collapse and form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function. Most stars do not form in isolation but as part of a group of stars referred as star clusters or stellar associations. First stars Star formation is divided into three groups called "Populations". Population III stars formed from primordial hydrogen after the Big Bang. These stars are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 4302
NGC 4302 is an edge-on Barred spiral galaxy, spiral galaxy located about 55 million light-years away in the constellation Coma Berenices. It was discovered by astronomer William Herschel on April 8, 1784 and is a member of the Virgo Cluster. It is classified as a Seyfert galaxy and as a LINER galaxy. It also has a prominent, extended dust lane. Physical characteristics The disk of NGC 4302 contains extraplanar dust that is organized into filamentary structures and large dust complexes. The apparent bending of many of the large complexes toward the north of the galaxy appears to be due to an interaction with the intracluster medium caused by the motion of NGC 4302 as it falls into the Virgo Cluster. The dense, dusty matter in the disk of NGC 4302 appears to be largely tracing matter ejected from the disk by energetic feedback from massive stars. Extraplanar Diffuse Ionized Gas First detected by Pildis et al., NGC 4302 has a faint but prominent layer of extraplanar diffuse ioniz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interacting Galaxy
Interacting galaxies (''colliding galaxies'') are galaxy, galaxies whose gravity, gravitational fields result in a disturbance of one another. Major mergers occur between galaxies with similar amounts of mass, whereas minor mergers involve galaxies with masses that vary significantly. An example of a minor interaction is a satellite galaxy disturbing the primary galaxy's spiral arms. An example of a major interaction is a galactic collision, which may lead to a galaxy merger. Satellite interaction A giant galaxy interacting with its satellite galaxy, satellites is common. A satellite's gravity could attract one of the primary's spiral arms. Alternatively, the secondary satellite can dive into the primary galaxy, as in the Sagittarius Dwarf Spheroidal Galaxy, Sagittarius Dwarf Elliptical Galaxy diving into the Milky Way. That can possibly trigger a small amount of star formation. Such orphaned clusters of stars were sometimes referred to as "blue blobs" before they were recognize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
