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Struve 1341
HD 80606 and HD 80607 are two stars comprising a binary star system. They are 215 light-years away in the constellation of Ursa Major. Both stars orbit each other at an average distance of 1,200 astronomical units. The binary system is listed as Struve 1341 in the Struve Catalogue of Double Stars; however, this designation is not in wide use and the system is usually referred to by the HD designations of its constituent stars. An extrasolar planet has been confirmed to orbit HD 80606 in a highly elliptical orbit. Stellar system The binary system components are very similar G-type main sequence stars with similar properties to the Sun, although both are older than the Sun and approaching the very end of their main sequence lives. Planetary system The variable radial velocity of HD 80606 was first noticed in 1999 from observations with the 10-m Keck 1 telescope at the W. M. Keck Observatory in Hawaii by the G-Dwarf Planet Search, a survey of nearly 1,000 nearby G dwarf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 80606 HD 80607 GALEX WikiSky
HD may refer to: Business * H-D or Harley-Davidson, a motorcycle manufacturer * The Home Depot, NYSE stock symbol: HD Chemistry * Hydrogen deuteride, a diatomic compound of hydrogen and deuterium * Mustard gas Codes * Air Do, formerly Hokkaido International Airlines, IATA designator * HD postcode area, covering Huddersfield, Brighouse and Holmfirth in England, UK * Heidelberg's vehicle registration plate code * Hunedoara County (Romania)'s ISO 3166 code Medicine * Hansen's disease or leprosy * Hirschsprung's disease, a disorder of the abdomen * Huntington's disease, a genetic disorder affecting the central nervous system ** HD (gene) or huntingtin, the IT15 gene, which codes for the huntingtin protein People * H.D. or Hilda Doolittle (1886–1961), American poet and novelist Other uses * ''Helsingborgs Dagblad'', a Swedish newspaper * Henry Draper Catalogue, an astronomical catalogue often used to designate stars * Department of Highways (other) * Supreme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geneva Extrasolar Planet Search
The Geneva Extrasolar Planet Search is a variety of observational programs run by the Geneva Observatory at Versoix, a small town near Geneva, Switzerland. The programs are executed by M. Mayor, D. Naef, F. Pepe, D. Queloz, N.C. Santos, and S. Udry using several telescopes and instruments in the Northern and Southern Hemisphere and have resulted in the discovery of numerous extrasolar planets, including 51 Pegasi b, the first ever confirmed exoplanet orbiting a main-sequence star. Programs originated at Geneva are generally conducted in collaboration with several other academic institutions from Belgium, Germany, Italy and the United Kingdom. These programs search for exoplanets in various locations using different instruments. These include the Haute-Provence Observatory in France, the TRAPPIST and the Euler Telescope, both located at La Silla Observatory in Chile, as well as the M dwarf programs. Most recent projects involve the HARPS spectrograph, HARPS-N at the island of L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Letters
Letter, letters, or literature may refer to: Characters typeface * Letter (alphabet), a character representing one or more of the sounds used in speech or none in the case of a silent letter; any of the symbols of an alphabet * Letterform, the graphic form of a letter of the alphabet, either as written or in a particular type font * Rehearsal letter in an orchestral score Communication * Letter (message), a form of written communication ** Mail * Letters, the collected correspondence of a writer or historically significant person **Pauline epistles, addressed by St. Paul to various communities or congregations, such as "Letters to the Galatians" or "Letters to the Corinthians", and part of the canonical books of the Bible ** Maktubat (other), the Arabic word for collected letters * The letter as a form of second-person literature; see Epistle ** Epistulae (Pliny) ** Epistolary novel, a long-form fiction composed of letters (epistles) * Open letter, a public letter as d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iota Horologii
Iota Horologii, Latinisation of names, Latinized from ι Horologii, is a star in the Horologium (constellation), Horologium constellation. With an apparent magnitude of +5.40, it can be seen to the naked eye only from places not affected by light pollution. Based on parallax measurements, it lies 56.5 light-years away. With a spectral type of G0Vp, this is a G-dwarf star, like the Sun, currently fusing hydrogen atoms into helium. It has previously been classified as G3 and a subgiant [IV]. It has 1.21 times the mass of the Sun and 1.16 times the solar radius, radius. Iota Horologii shines with 1.64 times the Solar luminosity, Sun's energy output from its photosphere, whose effective temperature is 6,200 Kelvin, K. At this temperature, Iota Horologii has the yellow-white hue typical of early G-type stars. Its age is about one-tenth as that of the Sun, 480 million years, albeit with a large margin of error of 75%. In 1999, a planet of the star was discovered. Because ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gliese 752
Gliese 752 is a binary star system in the Aquila constellation. This system is relatively nearby, at a distance of . The Gliese 752 system consists of two M-type stars. The primary star is the magnitude 9 ''Gliese (GJ) 752 A''. The secondary star is the dim magnitude 17 ''Gliese (GJ) 752 B'', more commonly referred to as '' VB 10''. This stellar pair form a binary star system separated by about 74 arc seconds (~434 AU). This system is also known for its high proper motion of about 1 arc second a year. Component A has one known exoplanet. The name and number are from the '' Catalogue of Nearby Stars'', published by German astronomer Wilhelm Gliese in 1969. Gliese 752 A characteristics The primary star, also known as ''Wolf 1055'', is a type M2.5 red dwarf with about half the size and mass as the Sun and considerably cooler at . This star was first observed to be a high proper motion star by the German astronomer Max Wolf with his pioneering use of astrophotograp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jupiter Mass
The Jupiter mass, also called Jovian mass, is the unit of mass equal to the total mass of the planet Jupiter. This value may refer to the mass of the planet alone, or the mass of the entire Jovian system to include the moons of Jupiter. Jupiter is by far the most massive planet in the Solar System. It is approximately 2.5 times as massive as all of the other planets in the Solar System combined. Jupiter mass is a common unit of mass in astronomy that is used to indicate the masses of other similarly-sized objects, including the outer planets, extrasolar planets, and brown dwarfs, as this unit provides a convenient scale for comparison. Current best estimates The current best known value for the mass of Jupiter can be expressed as : M_\mathrm=(1.89813 \pm 0.00019)\times10^ \text, which is about as massive as the Sun (is about ): M_\mathrm=\frac M_ \approx (9.547919 \pm 0.000002) \times10^ M_. Jupiter is 318 times as massive as Earth: M_\mathrm = 3.1782838 \times 10^2 M_\o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kirkwood Gap
A Kirkwood gap is a gap or dip in the distribution of the semi-major axes (or equivalently of the orbital periods) of the orbits of main-belt asteroids. They correspond to the locations of orbital resonances with Jupiter. The gaps were first noticed in 1866 by Daniel Kirkwood, who also correctly explained their origin in the orbital resonances with Jupiter while a professor at Jefferson College in Canonsburg, Pennsylvania. For example, there are very few asteroids with semimajor axis near 2.50 AU, period 3.95 years, which would make three orbits for each orbit of Jupiter (hence, called the 3:1 orbital resonance). Other orbital resonances correspond to orbital periods whose lengths are simple fractions of Jupiter's. The weaker resonances lead only to a depletion of asteroids, while spikes in the histogram are often due to the presence of a prominent asteroid family ''(see List of asteroid families)''. Most of the Kirkwood gaps are depleted, unlike the mean-motion resonance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kozai Mechanism
In celestial mechanics, the Kozai mechanism is a dynamical phenomenon affecting the orbit of a binary system perturbed by a distant third body under certain conditions. The mechanism is also named von Zeipel-Kozai-Lidov, Lidov–Kozai, Kozai–Lidov, etc., and may be termed an ''effect'', ''oscillation'', ''cycle'', or ''resonance''. This effect causes the orbit's argument of pericenter to oscillate about a constant value, which in turn leads to a periodic exchange between its eccentricity and inclination. The process occurs on timescales much longer than the orbital periods. It can drive an initially near-circular orbit to arbitrarily high eccentricity, and ''flip'' an initially moderately inclined orbit between a prograde and a retrograde motion. The effect has been found to be an important factor shaping the orbits of irregular satellites of the planets, trans-Neptunian objects, extrasolar planets, and multiple star systems. It hypothetically promotes black hole mergers. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar System" and "solar system" structures in theinaming guidelines document. The name is commonly rendered in lower case ('solar system'), as, for example, in the ''Oxford English Dictionary'' an''Merriam-Webster's 11th Collegiate Dictionary''. is the gravitationally bound Planetary system, system of the Sun and the objects that orbit it. It Formation and evolution of the Solar System, formed about 4.6 billion years ago when a dense region of a molecular cloud collapsed, forming the Sun and a protoplanetary disc. The Sun is a typical star that maintains a hydrostatic equilibrium, balanced equilibrium by the thermonuclear fusion, fusion of hydrogen into helium at its stellar core, core, releasing this energy from its outer photosphere. As ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comet Halley
Halley's Comet is the only known short-period comet that is consistently visible to the naked eye from Earth, appearing every 72–80 years, though with the majority of recorded apparitions (25 of 30) occurring after 75–77 years. It last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061. Officially designated 1P/Halley, it is also commonly called Comet Halley, or sometimes simply Halley. Halley's periodic returns to the inner Solar System have been observed and recorded by astronomers around the world since at least 240 BC, but it was not until 1705 that the English astronomer Edmond Halley understood that these appearances were re-appearances of the same comet. As a result of this discovery, the comet is named after Halley. During its 1986 visit to the inner Solar System, Halley's Comet became the first comet to be observed in detail by a spacecraft, ''Giotto'', providing the first observational data on the structure of a comet nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 20782
HD 20782 (HIP 15527; LTT 1582) is the primary of a wide binary system located in the southern constellation Fornax. It has an apparent magnitude of 7.38, making it readily visible in binoculars but not to the naked eye. The system is located relatively close at a distance of 117 light-years based on Gaia DR3 parallax measurements, but it is receding with a heliocentric radial velocity of . At its current distance, HD 20782's brightness is diminished by 0.12 magnitudes due to interstellar extinction and it has an absolute magnitude of +4.61. Properties HD 20782 has a stellar classification of G1.5 V, indicating that it is an ordinary G-type main-sequence star like the Sun. It has also been given a cooler class of G3 V. It has 96% the mass of the Sun and 1.17 times the radius of the Sun. It radiates 1.262 times the luminosity of the Sun from its photosphere at an effective temperature of , which is 35 K cooler than the Sun's temperature. When viewed in the night sky. the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eccentricity (orbit)
In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values between 0 and 1 form an elliptic orbit, 1 is a parabolic escape orbit (or capture orbit), and greater than 1 is a hyperbola. The term derives its name from the parameters of conic sections, as every Kepler orbit is a conic section. It is normally used for the isolated two-body problem, but extensions exist for objects following a rosette orbit through the Galaxy. Definition In a two-body problem with inverse-square-law force, every orbit is a Kepler orbit. The eccentricity of this Kepler orbit is a non-negative number that defines its shape. The eccentricity may take the following values: * Circular orbit: * Elliptic orbit: * Parabolic trajectory: * Hyperbolic trajectory: The eccentricity is given by e = \sqrt where is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
