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38 Leda
Leda ( minor planet designation: 38 Leda) is a large, dark main-belt asteroid that was discovered by French astronomer J. Chacornac on January 12, 1856, and named after Leda, the mother of Helen of Troy in Greek mythology. In the Tholen classification system, it is categorized as a carbonaceous C-type asteroid, while the Bus asteroid taxonomy system lists it as a Cgh asteroid. The spectra of the asteroid displays evidence of aqueous alteration. Leda has been studied by radar. During 2002, 38 Leda was observed by radar from the Arecibo Observatory. The return signal matched an effective diameter of 116 ± 13 km. This is consistent with the asteroid dimensions computed through other means. Based upon a light curve that was generated from photometric observations of this asteroid at Pulkovo Observatory, it has a rotation period of 12.834 ± 0.001 hours and varies in brightness by 0.15 ± 0.01 in magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jean Chacornac
Jean Chacornac (21 June 1823 – 23 September 1873) was a French astronomer and discoverer of a comet and several asteroids. He was born in Lyon and died in Saint-Jean-en-Royans, southeastern France. Working in Marseille and Paris, he discovered six asteroids in the asteroid belt ''(see table)'' and C/1852 K1 (Chacornac), a parabolic comet in 1852. This comet is thought to be the source of the current Eta Eridanids meteors. He also independently discovered 20 Massalia, which discovery is credited to the Italian astronomer Annibale de Gasparis, however. Jean Chacornac was awarded the Lalande Prize in 1855, 1856 and in 1863. The asteroid 1622 Chacornac and the lunar crater '' Chacornac'' are named in his honour. References External links J. Chacornac@ Astrophysics Data System The SAO/NASA Astrophysics Data System (ADS) is an online database of over 16 million astronomy and physics papers from both peer reviewed and non-peer reviewed sources. Abstracts are availabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid Taxonomy
An asteroid spectral type is assigned to asteroids based on their emission spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally differentiated, the surface and internal compositions are presumably similar, while large bodies such as Ceres and Vesta are known to have internal structure. Over the years, there has been a number of surveys that resulted in a set of different taxonomic systems such as the Tholen, SMASS and Bus–DeMeo classifications. Taxonomic systems In 1975, astronomers Clark R. Chapman, David Morrison, and Ben Zellner developed a simple taxonomic system for asteroids based on color, albedo, and spectral shape. The three categories were labelled " C" for dark carbonaceous objects, " S" for stony (silicaceous) objects, and "U" for those that did not fit into either C or S. This basic division of asteroid spectra has since been expanded and clarified.Thomas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C-type Asteroids (Tholen)
C-type (carbonaceous) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks and minerals. Their density averages at about . They occur most frequently at the outer edge of the asteroid belt, 3.5 astronomical units (AU) from the Sun, where 80% of the asteroids are of this type, whereas only 40% of asteroids at 2 AU from the Sun are C-type. The proportion of C-types may actually be greater than this, because C-types are much darker (and therefore less detectable) than most other asteroid types except for D-types and others that are mostly at the extreme outer edge of the asteroid belt. Characteristics Asteroids of this class have spectra very similar to those of carbonaceous chondrite meteorites (types CI and CM). The latter are very close in chemical composition to the Sun and the primitive solar nebula min ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Named Minor Planets
Named may refer to something that has been given a name A name is a term used for identification by an external observer. They can identify a class or category of things, or a single thing, either uniquely, or within a given context. The entity identified by a name is called its referent. A persona .... Named may also refer to: * named (computing), a widely used DNS server * Naming (parliamentary procedure) * The Named (band), an American industrial metal group In literature: * '' The Named'', a fantasy novel by Marianne Curley * The Named, a fictional race of prehistoric big cats, depicted in '' The Books of the Named'' series by Clare Bell See also * Name (other) * Names (other) * Naming (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discoveries By Jean Chacornac
Discoveries may refer to: Music * ''Discoveries'' (Cannonball Adderley album), 1955 * ''Discoveries'' (Josh Nelson album), 2011 * ''Discoveries'' (Northlane album), 2011 Other uses * ''Discoveries'' (film), a 1939 British film * Discoveries (horse), a racehorse * ''Discoveries'' (Robertson Davies), a 2002 book by Robertson Davies * ''Discoveries'' (TV series), a Canadian youth science television series which aired on CBC Television in 1957 * ''Abrams Discoveries'', a series of illustrated non-fiction books published by Harry N. Abrams * ''Discoveries'', a work by William Butler Yeats, written in 1907 * ''Discoveries'', a magazine published by Cedars-Sinai Medical Center See also * Age of Discoveries * Discovery (other) Discovery may refer to: * Discovery (observation), observing or finding something unknown * Discovery (fiction), a character's learning something unknown * Discovery (law), a process in courts of law relating to evidence Discovery, The Discov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Background Asteroids
Background may refer to: Performing arts and stagecraft * Background actor * Background artist * Background light * Background music * Background story * Background vocals * ''Background'' (play), a 1950 play by Warren Chetham-Strode Recorded works * ''Background'' (1953 film), a British drama * ''Background'' (1973 film), a documentary * ''Background'' (TV series), a Canadian journalistic television series * ''Background'' (Lifetime album), 1992 * ''Background'' (Bassi Maestro album), 2002 Science and engineering * Background extinction rate * Background independence, a condition in theoretical physics * Background noise * Background radiation, the natural radiation that is always present in a location ** Background (astronomy), small amounts of light coming from otherwise dark parts of the sky ** Cosmic background (other) ** Gravitational wave background ** X-ray background * Background process, software that is running but not being displayed * St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnitude (astronomy)
In astronomy, magnitude is a unitless measure of the brightness of an object in a defined passband, often in the visible or infrared spectrum, but sometimes across all wavelengths. An imprecise but systematic determination of the magnitude of objects was introduced in ancient times by Hipparchus. The scale is logarithmic and defined such that a magnitude 1 star is exactly 100 times brighter than a magnitude 6 star. Thus each step of one magnitude is \sqrt \approx 2.512 times brighter than the magnitude 1 higher. The brighter an object appears, the lower the value of its magnitude, with the brightest objects reaching negative values. Astronomers use two different definitions of magnitude: apparent magnitude and absolute magnitude. The ''apparent'' magnitude () is the brightness of an object as it appears in the night sky from Earth. Apparent magnitude depends on an object's intrinsic luminosity, its distance, and the extinction reducing its brightness. The ''absolute'' magni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulkovo Observatory
The Pulkovo Astronomical Observatory (russian: Пулковская астрономическая обсерватория, Pulkovskaya astronomicheskaya observatoriya), officially named the Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo, is the principal astronomical observatory of the Russian Academy of Sciences. It is located 19 km south of Saint Petersburg on Pulkovo Heights above sea level. It is part of the UNESCO World Heritage Site Historic Centre of Saint Petersburg and Related Groups of Monuments. It was formerly known as the Imperial Observatory at Pulkowo. Early years The observatory was opened in 1839. Originally, it was a brainchild of the German/Russian astronomer Friedrich Georg Wilhelm von Struve, who would become its first director (in 1861, his son Otto Wilhelm von Struve succeeded him). The architect was Alexander Bryullov. The observatory was equipped with state-of-the-art devices, one of them being the a aperture ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photometry (astronomy)
Photometry, from Greek '' photo-'' ("light") and '' -metry'' ("measure"), is a technique used in astronomy that is concerned with measuring the flux or intensity of light radiated by astronomical objects. This light is measured through a telescope using a photometer, often made using electronic devices such as a CCD photometer or a photoelectric photometer that converts light into an electric current by the photoelectric effect. When calibrated against standard stars (or other light sources) of known intensity and colour, photometers can measure the brightness or apparent magnitude of celestial objects. The methods used to perform photometry depend on the wavelength region under study. At its most basic, photometry is conducted by gathering light and passing it through specialized photometric optical bandpass filters, and then capturing and recording the light energy with a photosensitive instrument. Standard sets of passbands (called a photometric system) are defined to all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Curve
In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequency interval or Frequency band, band. Light curves can be periodic, as in the case of eclipsing binary, eclipsing binaries, Cepheid variables, other periodic variables, and Methods of detecting extrasolar planets#Transit photometry, transiting extrasolar planets, or aperiodic, like the light curve of a nova, a cataclysmic variable star, a supernova or a Gravitational microlensing, microlensing event or binary as observed during occultation events. The study of the light curve, together with other observations, can yield considerable information about the physical process that produces it or constrain the physical theories about it. Variable stars Graphs of the apparent magnitude of a variable star over time are commonly used to visua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arecibo Observatory
The Arecibo Observatory, also known as the National Astronomy and Ionosphere Center (NAIC) and formerly known as the Arecibo Ionosphere Observatory, is an observatory in Barrio Esperanza, Arecibo, Puerto Rico owned by the US National Science Foundation (NSF). The observatory's main instrument was the Arecibo Telescope, a spherical reflector dish built into a natural sinkhole, with a cable-mount steerable receiver and several radar transmitters for emitting signals mounted above the dish. Completed in 1963, it was the world's largest single-aperture telescope for 53 years, surpassed in July 2016 by the Five-hundred-meter Aperture Spherical Telescope (FAST) in China. Following two breaks in cables supporting the receiver platform in mid-2020, the NSF decommissioned the telescope. A partial collapse of the telescope occurred on December 1, 2020, before controlled demolition could be conducted. In 2022, the NSF announced the telescope will not be rebuilt, with an educationa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Astronomy
Radar astronomy is a technique of observing nearby astronomical objects by reflecting radio waves or microwaves off target objects and analyzing their reflections. Radar astronomy differs from '' radio astronomy'' in that the latter is a passive observation (i.e., receiving only) and the former an active one (transmitting and receiving). Radar systems have been conducted for six decades applied to a wide range of Solar System studies. The radar transmission may either be pulsed or continuous. The strength of the radar return signal is proportional to the inverse fourth-power of the distance. Upgraded facilities, increased transceiver power, and improved apparatus have increased observational opportunities. Radar techniques provide information unavailable by other means, such as testing general relativity by observing Mercury and providing a refined value for the astronomical unit. Radar images provide information about the shapes and surface properties of solid bodies, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
