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K-type Main-sequence Star
A K-type main-sequence star, also referred to as a K-type dwarf or an orange dwarf, is a main-sequence (hydrogen-burning) star of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence stars ("red dwarfs") and yellow/white G-type main-sequence stars. They have masses between 0.6 and 0.9 times the mass of the Sun and surface temperatures between 3,900 and 5,300 K. These stars are of particular interest in the search for extraterrestrial life due to their stability and long lifespan. Well-known examples include Alpha Centauri B (K1 V) and Epsilon Indi (K5 V). Spectral standard stars The revised Yerkes Atlas system (Johnson & Morgan 1953) listed 12 K-type dwarf spectral standard stars, however not all of these have survived to this day as standards. The "anchor points" of the MK classification system among the K-type main-sequence dwarf stars, i.e. those standard stars that have remain unchanged over the years, are: *Sigm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
61 Cygni Proper Motion
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61 may refer to: * 61 (number) * one of the years 61 BC, AD 61, 1961, 2061 * In some countries, a slang name for the Cyrillic letter Ы * '' 61*'', a 2001 American sports drama film * "Sixty One", a song by Karma to Burn from the album ''Mountain Czar'', 2016 See also List of highways numbered 61 The following highways are numbered 61: International * Asian Highway 61 * European route E61 Canada * Alberta Highway 61 * Newfoundland and Labrador Route 61 * Ontario Highway 61 India * National Highway 61 (India) Korea, South * National R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminosity
Luminosity is an absolute measure of radiated electromagnetic power (light), the radiant power emitted by a light-emitting object over time. In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a star, galaxy, or other astronomical object. In SI units, luminosity is measured in joules per second, or watts. In astronomy, values for luminosity are often given in the terms of the luminosity of the Sun, ''L''⊙. Luminosity can also be given in terms of the astronomical magnitude system: the absolute bolometric magnitude (''M''bol) of an object is a logarithmic measure of its total energy emission rate, while absolute magnitude is a logarithmic measure of the luminosity within some specific wavelength range or filter band. In contrast, the term ''brightness'' in astronomy is generally used to refer to an object's apparent brightness: that is, how bright an object appears to an observer. Apparent brightness depends on both the lum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrestrial Planet
A terrestrial planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, Venus, Earth and Mars. Among astronomers who use the geophysical definition of a planet, two or three planetary-mass satellites – Earth's Moon, Io, and sometimes Europa – may also be considered terrestrial planets; and so may be the rocky protoplanet-asteroids Pallas and Vesta.Emily Lakdawalla et al.What Is A Planet?The Planetary Society, 21 April 2020 The terms "terrestrial planet" and "telluric planet" are derived from Latin words for Earth (''Terra'' and ''Tellus''), as these planets are, in terms of structure, ''Earth-like''. Terrestrial planets are generally studied by geologists, astronomers, and geophysicists. Terrestrial planets have a solid planetary surface, making them substantially different from the larger gaseou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program, aeronautics research, and outer space, space research. NASA was National Aeronautics and Space Act, established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo program, Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion (spacecraft), Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew Program, Commercial Crew ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Scientist
''New Scientist'' is a magazine covering all aspects of science and technology. Based in London, it publishes weekly English-language editions in the United Kingdom, the United States and Australia. An editorially separate organisation publishes a monthly Dutch-language edition. First published on 22 November 1956, ''New Scientist'' has been available in online form since 1996. Sold in retail outlets (paper edition) and on subscription (paper and/or online), the magazine covers news, features, reviews and commentary on science, technology and their implications. ''New Scientist'' also publishes speculative articles, ranging from the technical to the philosophical. ''New Scientist'' was acquired by Daily Mail and General Trust (DMGT) in March 2021. History Ownership The magazine was founded in 1956 by Tom Margerison, Max Raison and Nicholas Harrison as ''The New Scientist'', with Issue 1 on 22 November 1956, priced at one shilling (a twentieth of a pound in pre-decimal UK ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gliese 529
This list of nearest bright stars is a table of stars found within 15 parsecs (48.9 light-years) of the nearest star, the Sun, that have an absolute magnitude of +8.5 or brighter, which is approximately comparable to a listing of stars more luminous than a red dwarf. Right ascension and declination coordinates are for the epoch J2000. The distance measurements are based on the Hipparcos Catalogue and other astrometric data. In the event of a spectroscopic binary, the combined spectral type and absolute magnitude are listed in ''italics''. The list is ordered by increasing distance. Stars within 10 parsecs These stars are estimated to be within 32.6 light years of the Sun. Stars between 10 and 13 parsecs These stars are estimated to be from 32.7 to 42.4 light years distant from the Sun. Stars between 13 and 15 parsecs These stars are estimated to be from 42.5 to 48.9 light years distant from the Sun. A value of 48.9 light years corresponds to a minimum parallax of 66.7 mas. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TW Piscis Austrini
TW Piscis Austrini (also Fomalhaut B) is a dwarf star in the constellation Piscis Austrinus. It lies relatively close to the Sun, at an estimated distance of 24.8 light-years. To an observer on Earth the star is visually separated from its larger companion Fomalhaut A by 2 degrees—the width of four full moons. The TW in the name is a variable star designation. This is a variable star of the type known as a BY Draconis variable, with surface brightness variations causing the changes as the star rotates. It varies slightly in apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's ..., ranging from 6.44 to 6.51 over a 10.3-day period. TW Piscis Austrini lies within a light-year of Fomalhaut A. Due to sharing the same proper motion, and the same estimated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 219134
HD 219134 (also known as Gliese 892 or HR 8832) is a main-sequence star in the constellation of Cassiopeia. It is smaller and less luminous than the Sun, with a spectral class of K3V, which makes it an orange-hued star. HD 219134 is relatively close to our system, with an estimated distance of 21.34 light years. This star is close to the limit of apparent magnitude that can still be seen by the unaided eye. The limit is considered to be magnitude 6 for most observers. This star has a magnitude 9.4 optical companion at an angular separation of 106.6 arcseconds. Planetary system HD 219134 has a system of six known exoplanets. The innermost planet, HD 219134 b, is a rocky super-Earth based on size (1.6 times the size of Earth), and density (6.4 grams per cubic cm). This and three additional exoplanets; one super-Earth (designated ''c'' and later found to be rocky as well), one Neptunian Neptune was discovered in 1846 and has only made occasional appearances in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
107 Piscium
107 Piscium is a single star in the constellation of Pisces. ''107 Piscium'' is the star's Flamsteed designation. John Flamsteed numbered the stars of Pisces from 1 to 113, publishing his ''Catalogus Britannicus'' in 1725. He accidentally numbered 107 Piscium twice, as he also allocated it the designation of 2 Arietis. This star is faintly visible to the naked eye with an apparent visual magnitude that has been measured varying between 5.14 and 5.26. However, that finding of variation was not confirmed by subsequent observations and is most likely spurious data. It is located at a distance of about away from the Sun. 107 Piscium is drifting closer to the Sun with a radial velocity of −33.6, and is predicted to come as close as in around 135,800 years. This object is a K-type main-sequence star with a stellar classification of K1V, indicating it is generating energy from core hydrogen fusion. It is somewhat older than the Sun—approximately 6 billion years o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
70 Ophiuchi
70 Ophiuchi is a binary star system located 16.6 light years away from the Earth. It is in the constellation Ophiuchus. At magnitude 4 it appears as a dim star visible to the unaided eye away from city lights. History In the Ptolemy's 2nd-century Almagest star catalogue this star system is listed as a 4th magnitude star, the ''28th'' (or ''4th outside the constellation figure'') in ''Ophiuchus''. It is star ''No. 261'' in this catalogue. This star system was first catalogued as a binary star by William Herschel in the late 18th century in his study of binary stars. Herschel proved that this system is a gravitationally bound binary system where the two stars orbit around a common center of mass. This was an important contribution to the proof that Newton's law of universal gravitation applied to objects beyond the Solar System. He commented at the time that there was a possible third ''unseen companion'' affecting the orbit of the two visible stars. Variability 70 O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
61 Cygni
61 Cygni is a binary star system in the constellation Cygnus, consisting of a pair of K-type dwarf stars that orbit each other in a period of about 659 years. Of apparent magnitude 5.20 and 6.05, respectively, they can be seen with binoculars in city skies or with the naked eye in rural areas without photopollution. 61 Cygni first attracted the attention of astronomers when its large proper motion was first demonstrated by Giuseppe Piazzi in 1804. In 1838, Friedrich Bessel measured its distance from Earth at about 10.4 light-years, very close to the actual value of about 11.4 light-years; this was the first distance estimate for any star other than the Sun, and first star to have its stellar parallax measured. Among all stars or stellar systems listed in the modern ''Hipparcos Catalogue'', 61 Cygni has the seventh-highest proper motion, and the highest among all visible stars or systems.By convention, limiting visual magnitude of 6.0 Over the cour ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epsilon Eridani
Epsilon Eridani ( Latinized from ε Eridani), formally named Ran, is a star in the southern constellation of Eridanus, at a declination of 9.46° south of the celestial equator. This allows it to be visible from most of Earth's surface. At a distance of from the Sun, it has an apparent magnitude of 3.73. It is the third-closest individual star or star system visible to the unaided eye. The star is estimated to be less than a billion years old. Because of its relative youth, Epsilon Eridani has a higher level of magnetic activity than the present-day Sun, with a stellar wind 30 times as strong. Its rotation period is 11.2 days at the equator. Epsilon Eridani is smaller and less massive than the Sun, and has a comparatively lower level of elements heavier than helium. It is a main-sequence star of spectral class K2, which means that energy generated at the core through nuclear fusion of hydrogen is emitted from the surface at a temperature of about , giving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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