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Sudarsky Extrasolar Planet Classification
Sudarsky's classification of gas giants for the purpose of predicting their appearance based on their temperature was outlined by David Sudarsky and colleagues in the paper ''Albedo and Reflection Spectra of Extrasolar Giant Planets'' and expanded on in ''Theoretical Spectra and Atmospheres of Extrasolar Giant Planets'', published before any successful direct or indirect observation of an extrasolar planet atmosphere was made. It is a broad classification system with the goal of bringing some order to the likely rich variety of extrasolar gas-giant atmospheres. Gas giants are split into five classes (numbered using Roman numerals) according to their modeled physical atmospheric properties. In the Solar System, only Jupiter and Saturn are within the Sudarsky classification, and both are Class I. The appearance of planets that are not gas giants cannot be predicted by the Sudarsky system, for example terrestrial planets such as Earth and Venus, or ice giants such as Uranus (14 Earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celestia
Celestia is a real-time 3D astronomy software program that was created in 2001 by Chris Laurel. The program allows users to virtually travel through our universe and explore real objects that have been catalogued. Celestia also doubles as a planetarium, but the user is not restricted to the Earth's surface, like in other planetarium software such as Stellarium. To summarize, Celestia is a scientifically accurate 3D universe simulator, that is also highly customizable. Celestia can display objects of various scales using OpenGL,There are three graphical front-ends available: GLUT, GTK+ or Qt. and the user can seamlessly transition between different scales, from entire galaxies to spacecraft a few meters across. Celestia is available for AmigaOS 4, Linux, macOS, Microsoft Windows, iOS, and Android. It is free and open source software released under the GNU General Public License. Celestia's development stopped in 2013, with the final release in 2011. Since then, some of i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albedo
Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that reflects all incident radiation. Surface albedo is defined as the ratio of radiosity ''J''e to the irradiance ''E''e (flux per unit area) received by a surface. The proportion reflected is not only determined by properties of the surface itself, but also by the spectral and angular distribution of solar radiation reaching the Earth's surface. These factors vary with atmospheric composition, geographic location, and time (see position of the Sun). While bi-hemispherical reflectance is calculated for a single angle of incidence (i.e., for a given position of the Sun), albedo is the directional integration of reflectance over all solar angles in a given period. The temporal resolution may range from seconds (as obtained from flux measurements) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upsilon Andromedae E
Upsilon Andromedae e is the proposed outermost extrasolar planet orbiting the star Upsilon Andromedae in the constellation of Andromeda. If it exists, this planet would be one of the most Jupiter-like exoplanets found in terms of mass and semi-major axis. However, subsequent studies have found that the apparent planetary signal is more likely to be an instrumental artifact. Discovery This planet was discovered on November 22, 2010, but the discovery paper was not released until December 2. It was the fourth time in 2010 that a fourth planet has been discovered in a planetary system, the others being Gliese 876 e, HD 10180 e, and HR 8799 e; in no earlier year during the exoplanet era had more than one fourth planet been discovered. Subsequent studies in 2011 and 2014, while finding some evidence for a fourth planet, found large inconsistencies in the estimated orbital period of Upsilon Andromedae e depending on what dataset was used, suggesting that the apparent planetary sign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
47 Ursae Majoris D
47 Ursae Majoris d (sometimes abbreviated 47 Uma d) is an extrasolar planet approximately 46 light-years away in the constellation of Ursa Major. The planet was discovered located in a long-orbital period, period orbit (38 years) around the star 47 Ursae Majoris. As of 2011, it is the outermost of three known planets in its planetary system. It has a mass of at least 1.64 times that of Jupiter. It is the longest-period planet detected by Doppler spectroscopy. The evidence of this planet was found by Bayesian Kepler periodogram in March 2010. References * 47 Ursae Majoris Exoplanets discovered in 2010 Giant planets Exoplanets detected by radial velocity {{extrasolar-planet-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
47 Ursae Majoris C
47 Ursae Majoris c (abbreviated 47 UMa c), formally named Taphao Kaew , is an extrasolar planet approximately 46 light-years from Earth in the constellation of Ursa Major. The planet was discovered located in a long- period around the star 47 Ursae Majoris. Its orbit lasts 6.55 years and the planet has a mass at least 0.540 times that of Jupiter. Name In July 2014 the International Astronomical Union launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning name was Taphao Kaew ( th, ตะเภาแก้ว ) for this planet. The winning name was submitted by the Thai Astronomical Society of Thailand. Taphaokaeo was one of two sisters associated with a Thai folk tale. Discovery Like many known extrasolar planets at the time, 47 Ursae Majoris c was discovered by detecting changes in its star's radial velocity caused ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Heat
{{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] |
Superjovian
A super-Jupiter is a gas giant exoplanet that is more massive than the planet Jupiter. For example, companions at the planet–brown dwarf borderline have been called super-Jupiters, such as around the star Kappa Andromedae. By 2011 there were 180 known super-Jupiters, some hot, some cold. Even though they are more massive than Jupiter, they remain about the same size as Jupiter up to 80 Jupiter masses. This means that their surface gravity and density go up proportionally to their mass. The increased mass compresses the planet due to gravity, thus keeping it from being larger. In comparison, planets somewhat lighter than Jupiter can be larger, so-called "puffy planets" (gas giants with a large diameter but low density). An example of this may be the exoplanet HAT-P-1b with about half the mass of Jupiter but about 1.38 times larger diameter. CoRoT-3b, with a mass around 22 Jupiter masses, is predicted to have an average density of 26.4 g/cm3, greater than osmium (22.6 g/cm3), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler's Laws Of Planetary Motion
In astronomy, Kepler's laws of planetary motion, published by Johannes Kepler between 1609 and 1619, describe the orbits of planets around the Sun. The laws modified the heliocentric theory of Nicolaus Copernicus, replacing its circular orbits and epicycles with elliptical trajectories, and explaining how planetary velocities vary. The three laws state that: # The orbit of a planet is an ellipse with the Sun at one of the two foci. # A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. # The square of a planet's orbital period is proportional to the cube of the length of the semi-major axis of its orbit. The elliptical orbits of planets were indicated by calculations of the orbit of Mars. From this, Kepler inferred that other bodies in the Solar System, including those farther away from the Sun, also have elliptical orbits. The second law helps to establish that when a planet is closer to the Sun, it travels faster. The thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
