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Sednoids
A sednoid is a trans-Neptunian object with a perihelion well beyond the Kuiper cliff at . Only four objects are known from this population: 90377 Sedna, , 541132 Leleākūhonua (), and , but it is suspected that there are many more. All four have perihelia greater than . These objects lie outside an apparently nearly empty gap in the Solar System and have no significant interaction with the planets. They are usually grouped with the detached objects. Some astronomers, such as Scott Sheppard, consider the sednoids to be inner Oort cloud objects (OCOs), though the inner Oort cloud, or Hills cloud, was originally predicted to lie beyond 2,000 AU, beyond the aphelia of the three known sednoids. One attempt at a precise definition of sednoids is any body with a perihelion greater than and a semi-major axis greater than . However, this definition applies to objects such as , which has a perihelion at 50.02 AU and a semi-major axis of about 700 AU but it is thought to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sednoid Orbits
A sednoid is a trans-Neptunian object with a perihelion well beyond the Kuiper cliff at . Only four objects are known from this population: 90377 Sedna, , 541132 Leleākūhonua (), and , but it is suspected that there are many more. All four have perihelia greater than . These objects lie outside an apparently nearly empty gap in the Solar System and have no significant interaction with the planets. They are usually grouped with the detached objects. Some astronomers, such as Scott Sheppard, consider the sednoids to be inner Oort cloud objects (OCOs), though the inner Oort cloud, or Hills cloud, was originally predicted to lie beyond 2,000 AU, beyond the aphelia of the three known sednoids. One attempt at a precise definition of sednoids is any body with a perihelion greater than and a semi-major axis greater than . However, this definition applies to objects such as , which has a perihelion at 50.02 AU and a semi-major axis of about 700 AU but it is thought to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sednoid Apparent Magnitudes
A sednoid is a trans-Neptunian object with a perihelion well beyond the Kuiper cliff at . Only four objects are known from this population: 90377 Sedna, , 541132 Leleākūhonua (), and , but it is suspected that there are many more. All four have perihelia greater than . These objects lie outside an apparently nearly empty gap in the Solar System and have no significant interaction with the planets. They are usually grouped with the detached objects. Some astronomers, such as Scott Sheppard, consider the sednoids to be inner Oort cloud objects (OCOs), though the inner Oort cloud, or Hills cloud, was originally predicted to lie beyond 2,000 AU, beyond the aphelia of the three known sednoids. One attempt at a precise definition of sednoids is any body with a perihelion greater than and a semi-major axis greater than . However, this definition applies to objects such as , which has a perihelion at 50.02 AU and a semi-major axis of about 700 AU but it is thought to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trans-Neptunian Object
A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet in the Solar System that orbits the Sun at a greater average distance than Neptune, which has a semi-major axis of 30.1 astronomical units (au). Typically, TNOs are further divided into the classical and resonant objects of the Kuiper belt, the scattered disc and detached objects with the sednoids being the most distant ones. As of October 2020, the catalog of minor planets contains 678 numbered and more than 2,000 unnumbered TNOs. The first trans-Neptunian object to be discovered was Pluto in 1930. It took until 1992 to discover a second trans-Neptunian object orbiting the Sun directly, 15760 Albion. The most massive TNO known is Eris, followed by Pluto, , , and . More than 80 satellites have been discovered in orbit of trans-Neptunian objects. TNOs vary in color and are either grey-blue (BB) or very red (RR). They are thought to be composed of mixtures of rock, amorphous carbon and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
90377 Sedna
Sedna (minor-planet designation 90377 Sedna) is a dwarf planet in the outer reaches of the Solar System that is in the innermost part of its orbit; it is 84 astronomical units (AU), or 1.26×1010 km, from the Sun, almost three times farther than Neptune. Spectroscopy has revealed that Sedna's surface composition is largely a mixture of water, methane, and nitrogen ices with tholins, similar to those of some other trans-Neptunian objects. Its surface is one of the reddest among Solar System objects. Sedna, within estimated uncertainties, is tied with as the largest planetoid not known to have a moon. Sedna's orbit is one of the largest in the Solar System other than those of long-period comets, with its aphelion (farthest distance from the Sun) estimated at 937 AU. This is 31 times Neptune's distance from the Sun, or 5.5 light-days, and well beyond the closest portion of the heliopause, which defines the boundary of interstellar space. As of 2022, the dwarf planets ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
541132 Leleākūhonua
541132 Leleākūhonua (), provisionally designated , is an extreme trans-Neptunian object and sednoid in the outermost part of the Solar System. It was first observed on 13 October 2015, by astronomers at the Mauna Kea Observatories, Hawaii. Based on its discovery date near Halloween and the letters in its provisional designation , the object was informally nicknamed "The Goblin" by its discoverers and later named ''Leleākūhonua'', comparing its orbit to the flight of the Pacific golden plover. It was the third sednoid discovered, after and , and measures around in diameter. Discovery ''Leleākūhonua'' was first observed on 13 October 2015 at the Mauna Kea Observatory , by American astronomers David Tholen, Chad Trujillo and Scott Sheppard during their astronomical survey for objects located beyond the Kuiper Cliff. The unofficial discovery was publicly announced on 1 October 2018. The survey uses two principal telescopes: For the Northern hemisphere, the 8.2-meter Su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2012
2012 was designated as: * International Year of Cooperatives *International Year of Sustainable Energy for All Events January * January 12 – Violent protests occur in Bucharest, Romania, as two-day-old demonstrations continue against President Traian Băsescu's economic austerity measures. Clashes are reported in numerous Romanian cities between protesters and law enforcement officers. * January 13 – The passenger cruise ship ''Costa Concordia'' runs aground off the coast of Italy, causing 32 deaths. * January 23 – Iran–European Union relations: the European Union adopts an embargo against Iran in protest of its continued effort to enrich uranium. * January 27 – Spanair ceases operations after talks with Qatar Airways for a prospective takeover fall through. February * February 6 – The Diamond Jubilee of Queen Elizabeth II marks the 60th anniversary of her accession to the thrones of the United Kingdom, Canada, Australia, and New Zeal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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