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Kepler-186c
Kepler-186 is a main-sequence M1-type dwarf star, located 178.5 parsecs (582 light years) away in the constellation of Cygnus. The star is slightly cooler than the sun, with roughly half its metallicity. It is known to have five planets, including the first Earth-sized world discovered in the habitable zone: Kepler-186f. free version = http://www.nasa.gov/sites/default/files/files/kepler186_main_final.pdf The star hosts four other planets discovered so far, though they all orbit interior to the habitable zone. Star A number of previously unknown measurements of the star are known.VizieR Detailed Page for 2MASS 19543665+4357180, "This publication makes use of data products from the Two Micron All Sky Survey, which is a joint proj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-186
Kepler-186 is a main-sequence M1-type dwarf star, located 178.5 parsecs (582 light years) away in the constellation of Cygnus. The star is slightly cooler than the sun, with roughly half its metallicity. It is known to have five planets, including the first Earth-sized world discovered in the habitable zone: Kepler-186f. free version = http://www.nasa.gov/sites/default/files/files/kepler186_main_final.pdf The star hosts four other planets discovered so far, though they all orbit interior to the habitable zone. Star A number of previously unknown measurements of the star are known.VizieR Detailed Page for 2MASS 19543665+4357180, "This publication makes use of data products from the Two Micron All Sky Survey, which is a joint proj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-186d
Kepler-186 is a main-sequence M1-type dwarf star, located 178.5 parsecs (582 light years) away in the constellation of Cygnus. The star is slightly cooler than the sun, with roughly half its metallicity. It is known to have five planets, including the first Earth-sized world discovered in the habitable zone: Kepler-186f. free version = http://www.nasa.gov/sites/default/files/files/kepler186_main_final.pdf The star hosts four other planets discovered so far, though they all orbit interior to the habitable zone. Star A number of previously unknown measurements of the star are known.VizieR Detailed Page for 2MASS 19543665+4357180, "This publication makes use of data products from the Two Micron All Sky Survey, which is a joint proj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-186c
Kepler-186 is a main-sequence M1-type dwarf star, located 178.5 parsecs (582 light years) away in the constellation of Cygnus. The star is slightly cooler than the sun, with roughly half its metallicity. It is known to have five planets, including the first Earth-sized world discovered in the habitable zone: Kepler-186f. free version = http://www.nasa.gov/sites/default/files/files/kepler186_main_final.pdf The star hosts four other planets discovered so far, though they all orbit interior to the habitable zone. Star A number of previously unknown measurements of the star are known.VizieR Detailed Page for 2MASS 19543665+4357180, "This publication makes use of data products from the Two Micron All Sky Survey, which is a joint proj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-186b
Kepler 186b (also known as KOI-571.03) is an exoplanet located around 582 light-years away from Earth. Kepler-186b is orbiting a red dwarf known as Kepler-186, named after the space telescope A space telescope or space observatory is a telescope in outer space used to observe astronomical objects. Suggested by Lyman Spitzer in 1946, the first operational telescopes were the American Orbiting Astronomical Observatory, OAO-2 launched ... that found it. Kepler-186b is the innermost planet of its system, and thus not suitable for life. One year on the planet is only 3.884 days long due to its location near the parent star. It is tidally locked. As a result, one hemisphere is in eternal daylight while the other hemisphere is in endless darkness. The other planets in the system are Kepler-186c, d, e, and f, of which only Kepler-186f is habitable. References Transiting exoplanets Exoplanets discovered in 2014 Kepler-186 186b {{exoplanet-stub Cygnus (constellation) [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BY Draconis Variable
BY Draconis variables are variable stars of late spectral types, usually K or M, and typically belong to the main sequence. The name comes from the archetype for this category of variable star system, BY Draconis. They exhibit variations in their luminosity due to rotation of the star coupled with starspots, and other chromospheric activity. Resultant brightness fluctuations are generally less than 0.5 magnitudes. Light curves of BY Draconis variables are quasiperiodic. The period is close to the star's mean rotational rate. The light curve is irregular over the duration of the period and it changes slightly in shape from one period to the next. For the star BY Draconis the shape of the light curve over a period remained similar for a month. Nearby K and M stars that are BY Draconis variables include Barnard's Star, Kapteyn's Star, 61 Cygni, Ross 248, Lacaille 8760, Lalande 21185, and Luyten 726-8. Ross 248 is the first discovered BY Draconis variable, the variability havin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tidal Force
The tidal force is a gravitational effect that stretches a body along the line towards the center of mass of another body due to a gradient (difference in strength) in gravitational field from the other body; it is responsible for diverse phenomena, including tides, tidal locking, breaking apart of celestial bodies and formation of ring systems within the Roche limit, and in extreme cases, spaghettification of objects. It arises because the gravitational field exerted on one body by another is not constant across its parts: the nearest side is attracted more strongly than the farthest side. It is this difference that causes a body to get stretched. Thus, the tidal force is also known as the differential force, as well as a secondary effect of the gravitational field. In celestial mechanics, the expression ''tidal force'' can refer to a situation in which a body or material (for example, tidal water) is mainly under the gravitational influence of a second body (for example, the Eart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tidally Locked
Tidal locking between a pair of co-orbiting astronomical body, astronomical bodies occurs when one of the objects reaches a state where there is no longer any net change in its rotation rate over the course of a complete orbit. In the case where a tidally locked body possesses synchronous rotation, the object takes just as long to Rotation around a fixed axis, rotate around its own axis as it does to revolve around its partner. For example, the same side of the Moon always faces the Earth, although there is some libration, variability because the Moon's orbit is not perfectly circular. Usually, only the natural satellite, satellite is tidally locked to the larger body. However, if both the difference in mass between the two bodies and the distance between them are relatively small, each may be tidally locked to the other; this is the case for Pluto and Charon (moon), Charon. Alternative names for the tidal locking process are gravitational locking, captured rotation, and spin–orb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-186e
Kepler-186e (also known by its Kepler Object of Interest designation ''KOI-571.04'') is a confirmed exoplanet orbiting the red dwarf star Kepler-186, approximately 582 light years away from Earth in the constellation of Cygnus. It is near the optimistic habitable zone but probably not in it, possibly making it have a runaway greenhouse effect, like Venus. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. Four additional planets orbiting the star (all modestly larger than Earth) were also discovered. Physical characteristics Mass, orbit, and composition The exoplanet is only slightly larger than Earth, with a radius 1.27–1.33 times that of Earth. Its mass is not known but it is likely to have a similar composition to Earth, giving it a mass of about 2.29–2.72 times the mass of the Earth. Kepler-186e orbits an M-dwarf star with about 4% of the Sun's luminosity with an orbital p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Optics
Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effect of incoming wavefront distortions by deforming a mirror in order to compensate for the distortion. It is used in astronomical telescopes and laser communication systems to remove the effects of atmospheric distortion, in microscopy, optical fabrication and in retinal imaging systems to reduce optical aberrations. Adaptive optics works by measuring the distortions in a wavefront and compensating for them with a device that corrects those errors such as a deformable mirror or a liquid crystal array. Adaptive optics should not be confused with active optics, which works on a longer timescale to correct the primary mirror geometry. Other methods can achieve resolving power exceeding the limit imposed by atmospheric distortion, such as speckle imaging, aperture synthesis, and lucky imaging, or by moving outside the atmosphere with space telescopes, such as the Hubble Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speckle Imaging
Speckle imaging describes a range of high-resolution astronomical imaging techniques based on the analysis of large numbers of short exposures that freeze the variation of atmospheric turbulence. They can be divided into the shift-and-add ("''image stacking''") method and the speckle interferometry methods. These techniques can dramatically increase the resolution of ground-based telescopes, but are limited to bright targets. Explanation The principle of all the techniques is to take very short exposure images of astronomical targets, and then process those so as to remove the effects of astronomical seeing. Use of these techniques led to a number of discoveries, including thousands of binary stars that would otherwise appear as a single star to a visual observer working with a similar-sized telescope, and the first images of sunspot-like phenomena on other stars. Many of the techniques remain in wide use today, notably when imaging relatively bright targets. The resolution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemini Observatory
The Gemini Observatory is an astronomical observatory consisting of two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, which are located at two separate sites in Hawaii and Chile, respectively. The twin Gemini telescopes provide almost complete coverage of both the northern and southern skies. They are currently among the largest and most advanced optical/infrared telescopes available to astronomers. ''(See List of largest optical reflecting telescopes)''. The National Science Foundation (NSF) of the United States, the National Research Council of Canada, CONICYT of Chile, MCTI of Brazil, and MCTIP of Argentina own and operate the Gemini Observatory. The NSF is currently (2017) the majority partner, contributing approximately 70% of the funding needed to operate and maintain both telescopes. The operations and maintenance of the observatory is managed by the Association of Universities for Research in Astronomy (AURA), through a cooperative agreement with NSF. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space
Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as spacetime. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework. Debates concerning the nature, essence and the mode of existence of space date back to antiquity; namely, to treatises like the ''Timaeus'' of Plato, or Socrates in his reflections on what the Greeks called ''khôra'' (i.e. "space"), or in the ''Physics'' of Aristotle (Book IV, Delta) in the definition of ''topos'' (i.e. place), or in the later "geometrical conception of place" as "spac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
