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Dwarf planet

Dwarf planet
Pluto in approximate true colour based on Hubble Space Telescope albedo data A dwarf planet is an object the size of a planet (a planetary-mass object) but that is neither a planet nor a moon or other natural satellite. More explicitly, the International Astronomical Union (IAU) defines a dwarf planet as a celestial body in direct orbit of the Sun[1] that is massive enough for its shape to be controlled by gravity, but that unlike a planet has not cleared its orbit of other objects.[2][3] However, only two of these bodies, Ceres and Pluto, have been observed in enough detail to demonstrate that they actually fit the IAU's definition. The IAU accepted Eris as a dwarf planet because it is more massive than Pluto. The classification of bodies in other planetary systems with the characteristics of dwarf planets has not been addressed.[17] History of the concept[edit] The IAU's final Resolution 5A preserved this three-category system for the celestial bodies orbiting the Sun. Name[edit]

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Terrestrial planet Structure[edit] Solar terrestrial planets[edit] Relative masses of the terrestrial planets of the Solar System, including the Moon During the formation of the Solar System, there were probably many more "terrestrial" planetesimals, but most merged with or were ejected by the four terrestrial planets. Density trends[edit] The uncompressed density of a terrestrial planet is the average density its materials would have at zero pressure. Eris (dwarf planet) Eris (minor-planet designation 136199 Eris) is the most-massive known dwarf planet in the Solar System and the ninth-most-massive body known to directly orbit the Sun.[d] It is estimated to be 2,326 (±12) km in diameter,[9] and 27% more massive than Pluto, or about 0.27% of the Earth's mass.[10][17] Routine observations were taken by the team on October 21, 2003, using the 1.2 m Samuel Oschin Schmidt telescope at Mount Palomar Observatory, California, but the image of Eris was not discovered at that point due to its very slow motion across the sky: The team's automatic image-searching software excluded all objects moving at less than 1.5 arcseconds per hour to reduce the number of false positives returned. When Sedna was discovered, it was moving at 1.75 arcsec/h, and in light of that the team reanalyzed their old data with a lower limit on the angular motion, sorting through the previously excluded images by eye. Distribution of trans-Neptunian objects

CH star CH stars are particular type of carbon stars which are characterized by the presence of exceedingly strong CH absorption bands in their spectra. They belong to the star population II, meaning they're metal poor and generally pretty middle-aged stars, and are underluminous compared to the classical C–N carbon stars. Many CH stars are known to be binaries, and it's reasonable to believe this is the case for all CH stars. Pluto In 2015, the Pluto system is due to be visited by spacecraft for the first time. The New Horizons probe will perform a flyby during which it will attempt to take detailed measurements and images of the plutoid and its moons. Discovery Discovery photographs of Pluto Astrochemistry Astrochemistry is the study of the abundance and reactions of chemical elements and molecules in the universe, and their interaction with radiation.[citation needed] The discipline is an overlap of astronomy and chemistry. The word "astrochemistry" may be applied to both the Solar System and the interstellar medium. The study of the abundance of elements and isotope ratios in Solar System objects, such as meteorites, is also called cosmochemistry, while the study of interstellar atoms and molecules and their interaction with radiation is sometimes called molecular astrophysics. The formation, atomic and chemical composition, evolution and fate of molecular gas clouds is of special interest, because it is from these clouds that solar systems form. Spectroscopy[edit]

Ceres (dwarf planet) From Earth, the apparent magnitude of Ceres ranges from 6.7 to 9.3, and hence even at its brightest it is too dim to be seen with the naked eye except under extremely dark skies. Piazzi's book "Della scoperta del nuovo pianeta Cerere Ferdinandea" outlining the discovery of Ceres, dedicated the new "planet" to Ferdinand I of the Two Sicilies One of the astronomers selected for the search was Giuseppe Piazzi at the Academy of Palermo, Sicily. Before receiving his invitation to join the group, Piazzi discovered Ceres on 1 January 1801.[19] He was searching for "the 87th [star] of the Catalogue of the Zodiacal stars of Mr la Caille", but found that "it was preceded by another".[17] Instead of a star, Piazzi had found a moving star-like object, which he first thought was a comet.[20] Piazzi observed Ceres a total of 24 times, the final time on 11 February 1801, when illness interrupted his observations.

Primary Life Support System A Portable Life Support System from the Apollo A7L suit, with its outer cover removed A Primary (or Portable or Personal) Life Support System (or /Subsystem) (PLSS), is a device connected to an astronaut or cosmonaut's spacesuit, which allows extra-vehicular activity with maximum freedom, independent of a spacecraft's life support system. The PLSS is generally worn like a backpack. The functions performed by the PLSS include: regulating suit pressureproviding breathable oxygenremoving carbon dioxide, humidity, odors, and contaminants from breathing oxygencooling and recirculating oxygen through the pressure garment, and water through a Liquid Cooling and Ventilation Garment or Liquid Cooling Garment.two-way voice communicationdisplay and/or telemetry of suit health parameterstelemetry of an indicator of the wearer's immediate health (e.g. heart rate) Apollo PLSS[edit]

Haumea (dwarf planet) Two teams claim credit for the discovery of Haumea. Mike Brown and his team at Caltech discovered Haumea in December 2004 on images they had taken on May 6, 2004. On July 20, 2005, they published an online abstract of a report intended to announce the discovery at a conference in September 2005.[23] At around this time, José Luis Ortiz Moreno and his team at the Instituto de Astrofísica de Andalucía at Sierra Nevada Observatory in Spain found Haumea on images taken on March 7–10, 2003.[24] Ortiz emailed the Minor Planet Center with their discovery on the night of July 27, 2005.[24] Brown initially conceded discovery credit to Ortiz,[25] but came to suspect the Spanish team of fraud upon learning that his observation logs were accessed from the Spanish observatory the day before the discovery announcement. The proposal by the Ortiz team, Ataecina, did not meet IAU naming requirements, because Ataecina is not a creation deity.

ILC Dover EMU suit worn during EVA on the International Space Station ILC Dover, LP (also known as ILC) is an American special engineering development and manufacturing company based in Frederica, Delaware. ILC specializes in the use of high-performance flexible materials, serving the aerospace, personal protection, and pharmaceutical industries. Best known for making space suits for NASA, ILC outfitted every United States astronaut in the Apollo program, including the twelve that walked on the moon. ILC also designed and manufactured the Space Suit Assembly portion of the Extravehicular Mobility Unit (EMU), worn by astronauts during performance of extra-vehicular activity (EVA) on Space Shuttle missions and on the International Space Station. Makemake (dwarf planet) Makemake (minor-planet designation 136,472 Makemake) is a dwarf planet and perhaps the largest Kuiper belt object (KBO) in the classical population,[nb 2] with a diameter that is about 2/3 the size of Pluto.[10][18] Makemake has no known satellites, which makes it unique among the largest KBOs and means that its mass can only be estimated. Its extremely low average temperature, about 30 K (−243.2 °C), means its surface is covered with methane, ethane, and possibly nitrogen ices.[15] Despite its relative brightness (it is about a fifth as bright as Pluto),[nb 3] Makemake was not discovered until well after many much fainter Kuiper belt objects. Most searches for minor planets are conducted relatively close to the ecliptic (the region of the sky that the Sun, Moon and planets appear to lie in, as seen from Earth), due to the greater likelihood of finding objects there. The provisional designation 2005 FY9 was given to Makemake when the discovery was made public.

Fuzzball (string theory) Theorized fuzzballs, like classic black holes, distort spacetime and bend light. Here, the edge of the central dark spot, the event horizon, delineates not only the threshold where its escape velocity equals the speed of light but also a fuzzball’s physical surface. (Artist rendition) Fuzzballs are theorized by some superstring theory scientists to be the true quantum description of black holes. The theory resolves two intractable problems that classic black holes pose for modern physics: Astronomical object Above the round domes of La Silla Observatory, three astronomical objects in the Solar System — Jupiter (top), Venus (lower left), and Mercury (lower right).[1] Types of Solar System bodies. Astronomical objects or celestial objects are naturally occurring physical entities, associations or structures that current science has demonstrated to exist in the observable universe.[2] The term astronomical object is sometimes used interchangeably with astronomical body. Typically, an astronomical (celestial) body refers to a single, cohesive structure that is bound together by gravity (and sometimes by electromagnetism).

Interstellar nitrogen monohydride Nitrogen monohydride (NH) is a simple compound that has been detected in interstellar space. History[edit] One of the earliest papers on the NH molecule was in 1976 by Richard M. Crutcher and William D. Watson.