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162173 Ryugu
162173 Ryugu, provisional designation , is a near-Earth object and a potentially hazardous asteroid of the Apollo group. It measures approximately in diameter and is a dark object of the rare spectral type Cb, with qualities of both a C-type asteroid and a B-type asteroid. In June 2018, the Japanese spacecraft ''Hayabusa2'' arrived at the asteroid. After making measurements and taking samples, ''Hayabusa2'' left Ryugu for Earth in November 2019/ and returned the sample capsule to Earth on 5 December 2020. History Discovery and name Ryugu was discovered on 10 May 1999 by astronomers with the Lincoln Near-Earth Asteroid Research at the Lincoln Lab's ETS near Socorro, New Mexico, in the United States. It was given the provisional designation . The asteroid was officially named "Ryugu" by the Minor Planet Center on 28 September 2015 (). The name refers to Ryūgū-jō (Dragon Palace), a magical underwater palace in a Japanese folktale. In the story, the fisherman Urashima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hayabusa2
is an asteroid sample-return mission operated by the Japanese state space agency JAXA. It is a successor to the '' Hayabusa'' mission, which returned asteroid samples for the first time in June 2010. ''Hayabusa2'' was launched on 3 December 2014 and rendezvoused in space with near-Earth asteroid 162173 Ryugu on 27 June 2018. It surveyed the asteroid for a year and a half and took samples. It left the asteroid in November 2019 and returned the samples to Earth on 5 December 2020 UTC. Its mission has now been extended through at least 2031, when it will rendezvous with the small, rapidly-rotating asteroid . ''Hayabusa2'' carries multiple science payloads for remote sensing and sampling, and four small rovers to investigate the asteroid surface and analyze the environmental and geological context of the samples collected. Mission overview Asteroid 162173 Ryugu (formerly designated ) is a primitive carbonaceous near-Earth asteroid. Carbonaceous asteroids are thought ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid Spectral Types
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.Thoma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Heating
{{Unreferenced, date=February 2012 Internal heat is the heat source from the interior of celestial objects, such as stars, brown dwarfs, planets, moons, dwarf planets, and (in the early history of the Solar System) even asteroids such as Vesta, resulting from contraction caused by gravity (the Kelvin–Helmholtz mechanism), nuclear fusion, tidal heating, core solidification (heat of fusion released as molten core material solidifies), and radioactive decay. The amount of internal heating depends on mass; the more massive the object, the more internal heat it has; also, for a given density, the more massive the object, the greater the ratio of mass to surface area, and thus the greater the retention of internal heat. The internal heating keeps celestial objects warm and active. Small celestial objects In the early history of the Solar System, radioactive isotopes having a half-life on the order of a few million years (such as aluminium-26 and iron-60) were sufficiently abunda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
142 Polana
Polana (minor planet designation: 142 Polana) is a very dark asteroid from the asteroid belt. It was discovered by Johann Palisa on January 28, 1875, and named after the city of Pola (now Pula, Croatia), home of the Austrian Naval Observatory where he made the discovery. It is a major member of the eponymously named Polana family, which is a subgroup of the Nysa family. The asteroid has an estimated diameter of about 55.3 km and a low albedo of 0.045. It is orbiting at a distance of 2.419 times the separation of the Earth from the Sun, with an orbital period of 3.76 years and an eccentricity of 0.14. In the Tholen classification scheme, Polana is a primitive carbonaceous asteroid of type F, which is a subdivision of more common C-type. Under the SMASS classification taxonomy, Polana is listed as a B-type asteroid; a group that combines both the Tholen B and F types. The spectrum of this object suggests the presence of magnetite (Fe3O4), which gives it the spectra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
495 Eulalia
Eulalia (minor planet designation: 495 Eulalia) is a minor planet orbiting the Sun. Eulalia is very near the 3:1 Jupiter orbital resonance. It is possible that the disruption of Eulalia's parent body resulted in a mass bombardment of the Earth and Moon 800 million years ago, forming the Copernicus crater on the Moon and involving about 50 times the amount of material of the Chicxulub impact on Earth at the beginning of the Cryogenian The Cryogenian (from grc, κρύος, krýos, meaning "cold" and , romanized: , meaning "birth") is a geologic period that lasted from . It forms the second geologic period of the Neoproterozoic Era, preceded by the Tonian Period and followed by ... geological period.Terada, K., Morota, T. & Kato, MAsteroid shower on the Earth-Moon system immediately before the Cryogenian period revealed by KAGUYA.''Nature Communications'' 11, 3453 (2020). https://doi.org/10.1038/s41467-020-17115-6 References External links Lightcurve plot of 495 Eulali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid Family
An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions. An asteroid family is a more specific term than asteroid group whose members, while sharing some broad orbital characteristics, may be otherwise unrelated to each other. General properties Large prominent families contain several hundred recognized asteroids (and many more smaller objects which may be either not-yet-analyzed, or not-yet-discovered). Small, compact families may have only about ten identified members. About 33% to 35% of asteroids in the main belt are family members. There are about 20 to 30 reliably recognized families, with several tens of less certain groupings. Most asteroid families are found in the main asteroid belt, although several family-like groups such as the Pallas family, Hungaria family, and the Phocaea fam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tamatebako
A "jeweled hand box", "jewel box", "jeweled box", "treasure box", "casket", etc., is the name of a mysterious box that in the Japanese folk tale "Urashima Tarō", is a parting gift that the fisherman Urashima Tarō receives from mistress of the sea (Otohime), after his stay at the Dragon Palace (or Hōrai), to which he was invited after saving a turtle. ''Katami no hako'' "memento box" is another name by which the box is referred to in the tale. ''Tamakushige'' "comb box" is the name that occurs in earlier precursors, such as the anecdote of Ura-no-Shimako (Urashima-no-ko) in the ''Fudoki'' of Tango Province and the '' Manyōshū'' (8th century). The term ''tamatebako'' was first employed in reference to the tale in a quoted poem in ''Otogizōshi''. Etymology and aliases ''Tamatebako'' is literally rendered "jewel-hand-box" but sometimes it is seen as not imparting any special meaning and translated as "casket". It was glossed as meaning a "beautiful box" by McKeon. The fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urashima Tarō
is the protagonist of a Japanese fairy tale (''otogi banashi''), who in a typical modern version is a fisherman rewarded for rescuing a turtle, and carried on its back to the Dragon Palace (Ryūgū-jō) beneath the sea. There he is entertained by the princess Otohime as a reward. He spends what he believes to be several days with the princess, but when he returns to his home village, he discovers he has been gone for at least 100 years. When he opens the forbidden jewelled box (tamatebako), given to him by Otohime on his departure, he turns into an old man. The tale originates from the legend of Urashimako (Urashima no ko or Ura no Shimako) recorded in various pieces of literature dating to the 8th century, such as the ''Fudoki'' for Tango Province, '' Nihon Shoki'', and the ''Man'yōshū''. During the Muromachi to Edo periods, versions of '' Urashima Tarō'' appeared in storybook form called the '' Otogizōshi'', made into finely painted picture scrolls and picture books or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japanese Folklore
Japanese folklore encompasses the informally learned folk traditions of Japan and the Japanese people as expressed in its oral traditions, customs, and material culture. In Japanese, the term is used to describe folklore. The academic study of folklore is known as . Folklorists also employ the term or to refer to the objects and arts they study. Folk religion Men dressed as namahage, wearing ogre-like masks and traditional straw capes ('' mino'') make rounds of homes, in an annual ritual of the Oga Peninsula area of the Northeast region. These ogre-men masquerade as kami looking to instill fear in the children who are lazily idling around the fire. This is a particularly colorful example of folk practice still kept alive. A parallel custom is the secretive ritual of the Yaeyama Islands, Okinawa which does not allow itself to be photographed. Many, though increasingly fewer households maintain a kamidana or a small Shinto altar shelf. The Shinto version of the kitchen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minor Planet Circulars
The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function The Minor Planet Center is the official worldwide organization in charge of collecting observational data for minor planets (such as asteroids), calculating their orbits and publishing this information via the '' Minor Planet Circulars''. Under the auspices of the International Astronomical Union (IAU), it operates at the Smithsonian Astrophysical Observatory, which is part of the Center for Astrophysics along with the Harvard College Observatory. The MPC runs a number of free online services for observers to assist them in observing minor planets and comets. The complete catalogue of minor planet orbits (sometimes referred to as the "Minor Planet Catalogue") may also be freely downloaded. In addition to astrometric data, the MPC colle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minor Planet Center
The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function The Minor Planet Center is the official worldwide organization in charge of collecting observational data for minor planets (such as asteroids), calculating their orbits and publishing this information via the ''Minor Planet Circulars''. Under the auspices of the International Astronomical Union (IAU), it operates at the Smithsonian Astrophysical Observatory, which is part of the Center for Astrophysics along with the Harvard College Observatory. The MPC runs a number of free online services for observers to assist them in observing minor planets and comets. The complete catalogue of minor planet orbits (sometimes referred to as the "Minor Planet Catalogue") may also be freely downloaded. In addition to astrometric data, the MPC collects l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Provisional Designation In Astronomy
Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calculated. Approximately 47% of the more than 1,100,000 known minor planets remain provisionally designated, as hundreds of thousands have been discovered in the last two decades. __TOC__ Minor planets The current system of provisional designation of minor planets (asteroids, centaurs and trans-Neptunian objects) has been in place since 1925. It superseded several previous conventions, each of which was in turn rendered obsolete by the increasing numbers of minor planet discoveries. A modern or new-style provisional designation consists of the year of discovery, followed by two letters and, possibly, a suffixed number. New-style provisional designation For example, the provisional designation stands for the 3910th body identified du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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