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Alpha1 Capricorni
Alpha1 Capricorni, Latinized from α1 Capricorni, is a distant, binary star system dominated by a highly luminous star in the constellation of Capricornus, north of the ecliptic. It has the traditional star names Prima Giedi () and Algiedi Prima (). The system is separated from the brighter Alpha2 Capricorni by 0.11° of the sky, a gap resolvable with the naked eye, similar to Mizar and Alcor. Both are not to be confused with much fainter 3 Capricorni nor somewhat fainter Nu Capricorni which are 3 to 6 times the angular distance apart than separate the two Alpha stars, respectively. The primary star is a yellow hued supergiant star with a stellar classification of G3 Ib. It has an apparent magnitude of +4.3; bright enough to make it visible to the naked eye. The star is located at a distance of approximately 870 light years from the solar system based on parallax measurements, but is drifting closer with a radial velocity of −25 km/s. The star is pas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving the positions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Evolution
Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are formed from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star. Nuclear fusion powers a star for most of its existence. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, pass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
36 Ophiuchi
36 Ophiuchi (or Guniibuu for A) is a triple star system 19.5 light-years from Earth. It is in the constellation Ophiuchus. The primary and secondary stars (also known as HD 155886) are nearly identical orange main-sequence dwarfs of spectral type K2/K1. This binary is unusual because its eruptions do not seem to conform to the Waldmeier effect; that is, the strongest eruptions of HD 155886 are not the ones characterized by the fast eruption onset. The tertiary star is an orange main-sequence dwarf of spectral type K5. Star C is separated from the A-B pair by 700 arcseconds, compared to a minimum of 4.6 arcseconds for A-B, so its effect on the movements of the A-B pair is small. A and B have active chromospheres. At present the distance between the stars forming the AB-pair is 5.1 arcseconds and the position angle is 139 degrees, while star C is 731.6 arcseconds away from the A-component and situated at a position angle of 74 degrees. Nomenclature In the beliefs of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dune (novel)
''Dune'' is a 1965 epic science fiction novel by American author Frank Herbert, originally published as two separate serials in ''Analog'' magazine. It tied with Roger Zelazny's ''This Immortal'' for the Hugo Award in 1966 and it won the inaugural Nebula Award for Best Novel. It is the first installment of the ''Dune'' saga. In 2003, it was described as the world's best-selling science fiction novel. ''Dune'' is set in the distant future amidst a feudal interstellar society in which various noble houses control planetary fiefs. It tells the story of young Paul Atreides, whose family accepts the stewardship of the planet Arrakis. While the planet is an inhospitable and sparsely populated desert wasteland, it is the only source of melange, or "spice", a drug that extends life and enhances mental abilities. Melange is also necessary for space navigation, which requires a kind of multidimensional awareness and foresight that only the drug provides. As melange can only be prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Fiction
Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imagination, imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, Parallel universes in fiction, parallel universes, extraterrestrials in fiction, extraterrestrial life, sentient artificial intelligence, cybernetics, certain forms of immortality (like mind uploading), and the technological singularity, singularity. Science fiction List of existing technologies predicted in science fiction, predicted several existing inventions, such as the atomic bomb, robots, and borazon, whose names entirely match their fictional predecessors. In addition, science fiction might serve as an outlet to facilitate future scientific and technological innovations. Science fiction can trace its roots to ancient mythology. It is also related to fantasy, Horror fiction, horror, and superhero fiction and contains many #Subgenres, sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frank Herbert
Franklin Patrick Herbert Jr. (October 8, 1920February 11, 1986) was an American science fiction author best known for the 1965 novel ''Dune'' and its five sequels. Though he became famous for his novels, he also wrote short stories and worked as a newspaper journalist, photographer, book reviewer, ecological consultant, and lecturer. The ''Dune'' saga, set in the distant future, and taking place over millennia, explores complex themes, such as the long-term survival of the human species, human evolution, planetary science and ecology, and the intersection of religion, politics, economics and power in a future where humanity has long since developed interstellar travel and settled many thousands of worlds. ''Dune'' is the best-selling science fiction novel of all time, and the entire series is considered to be among the classics of the genre. Biography Early life Frank Patrick Herbert Jr. was born on October 8, 1920, in Tacoma, Washington, to Frank Patrick Herbert Sr. and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fictional Planet
Planets in science fiction are fictional planets that appear in various media of the science fiction genre as story-settings or depicted locations. Planet lists For planets from specific fictional milieux, use the following lists: Literature * ''Alliance–Union Universe'' by C. J. Cherryh: planet list * The works of Hal Clement: planet list * ''Childe Cycle'' by Gordon R. Dickson: planet list * ''Demon Princes'' by Jack Vance: planet list * ''Known Space'' by Larry Niven: planet list * ''Noon Universe'' by Arkady and Boris Strugatsky: planet list * '' The Three Worlds Cycle'' by Ian Irvine: planet list * ''Time Quintet'' by Madeleine L'Engle: planet list * ''Uplift'' by David Brin: planet list *Various works by Kurt Vonnegut: Tralfamadore (different planets with the same name) Comics * DC Comics: planet list * Marvel Comics: planet list Film and television * Marvel Cinematic Universe: planet list * ''Star Wars'': planet list Animation * ''Teenage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giedi Prime
''Dune'' is a 1965 epic science fiction novel by American author Frank Herbert, originally published as two separate serials in ''Analog'' magazine. It tied with Roger Zelazny's ''This Immortal'' for the Hugo Award in 1966 and it won the inaugural Nebula Award for Best Novel. It is the first installment of the ''Dune'' saga. In 2003, it was described as the world's best-selling science fiction novel. ''Dune'' is set in the distant future amidst a feudal interstellar society in which various noble houses control planetary fiefs. It tells the story of young Paul Atreides, whose family accepts the stewardship of the planet Arrakis. While the planet is an inhospitable and sparsely populated desert wasteland, it is the only source of melange, or "spice", a drug that extends life and enhances mental abilities. Melange is also necessary for space navigation, which requires a kind of multidimensional awareness and foresight that only the drug provides. As melange can only be pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proper Motion
Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more distant stars. The components for proper motion in the equatorial coordinate system (of a given epoch, often J2000.0) are given in the direction of right ascension (''μ''α) and of declination (''μ''δ). Their combined value is computed as the ''total proper motion'' (''μ''). It has dimensions of angle per time, typically arcseconds per year or milliarcseconds per year. Knowledge of the proper motion, distance, and radial velocity allows calculations of an object's motion from our star system's frame of reference and its motion from the galactic frame of reference – that is motion in respect to the Sun, and by coordinate transformation, that in respect to the Milky Way. Introduction Over the course of centuries, stars appear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Companion
In observational astronomy, a double star or visual double is a pair of stars that appear close to each other as viewed from Earth, especially with the aid of optical telescopes. This occurs because the pair either forms a binary star (i.e. a binary system of stars in mutual orbit, gravitationally bound to each other) or is an ''optical double'', a chance line-of-sight alignment of two stars at different distances from the observer. Binary stars are important to stellar astronomers as knowledge of their motions allows direct calculation of stellar mass and other stellar parameters. The only (possible) case of "binary star" whose two components are separately visible to the naked eye is the case of Mizar and Alcor (though actually a multiple-star system), but it is not known for sure whether Mizar and Alcor are gravitationally bound. Since the beginning of the 1780s, both professional and amateur double star observers have telescopically measured the distances and angles between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Separation
Angular distance \theta (also known as angular separation, apparent distance, or apparent separation) is the angle between the two sightlines, or between two point objects as viewed from an observer. Angular distance appears in mathematics (in particular geometry and trigonometry) and all natural sciences (e.g. astronomy and geophysics). In the classical mechanics of rotating objects, it appears alongside angular velocity, angular acceleration, angular momentum, moment of inertia and torque. Use The term ''angular distance'' (or ''separation'') is technically synonymous with ''angle'' itself, but is meant to suggest the linear distance between objects (for instance, a couple of stars observed from Earth). Measurement Since the angular distance (or separation) is conceptually identical to an angle, it is measured in the same units, such as degrees or radians, using instruments such as goniometers or optical instruments specially designed to point in well-defined direct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hipparcos
''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky. This permitted the first high-precision measurements of the intrinsic brightnesses (compared to the less precise apparent brightness), proper motions, and parallaxes of stars, enabling better calculations of their distance and tangential velocity. When combined with radial velocity measurements from spectroscopy, astrophysicists were able to finally measure all six quantities needed to determine the motion of stars. The resulting ''Hipparcos Catalogue'', a high-precision catalogue of more than 118,200 stars, was published in 1997. The lower-precision ''Tycho Catalogue'' of more than a million stars was published at the same time, while the enhanced Tycho-2 Catalogue of 2.5 million stars was published in 2000. ''Hipparcos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
