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HD 156668
HD 156668 is a star in the northern constellation of Hercules constellation. With an apparent visual magnitude of 8.4 it is too faint to be viewed with the naked eye, but it can be seen with even a small telescope. The distance to this object has been determined directly using the parallax technique, yielding a value of about . This star has the stellar classification of a K2 dwarf, with approximately 77% of the mass of the Sun and about 72% of the Sun's diameter. While they are on the main sequence, lower mass stars like this generate energy much more slowly than the Sun. As a result, this star is radiating only 23% of the Sun's bolometric luminosity. HD 156668 is emitting this energy from its outer atmosphere at an effective temperature of around 4850 K, giving it the cool orange glow of a K-type star. It is slightly more enriched in iron compared to the Sun and is rotating at a leisurely rate of once every 51.5 days. Although much older than the Sun, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a instant, 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 Astronomical object, celestial body, as they are subject to Perturbation (astronomy), 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 Perihelion and aphelion, 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 bodi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Draper
Henry Draper (March 7, 1837 – November 20, 1882) was an American doctor and amateur astronomer. He is best known today as a pioneer of astrophotography. Life and work Henry Draper's father, John William Draper, was an accomplished doctor, chemist, botanist, and professor at New York University; he was also the first to photograph the moon through a telescope (1840). Draper's mother was Antonia Coetana de Paiva Pereira Gardner, daughter of the personal physician to the Emperor of Brazil. His niece, Antonia Maury was also an astronomer. He graduated from New York University School of Medicine, at the age of 20, in 1857. He worked first as a physician at Bellevue Hospital, and later as both a professor and dean of medicine at New York University (NYU). On May 31, 1862, he joined S Company, 12th New York Infantry Regiment as a surgeon along with his brother John Christopher, who joined as an assistant surgeon.Hughes, Stefan''Catchers of the Light, Volume 1 - Catching Space'' Ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commonwealth Scientific And Industrial Research Organisation
The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is an Australian Government agency responsible for scientific research. CSIRO works with leading organisations around the world. From its headquarters in Canberra, CSIRO maintains more than 50 sites across Australia and in France, Chile and the United States, employing about 5,500 people. Federally funded scientific research began in Australia years ago. The Advisory Council of Science and Industry was established in 1916 but was hampered by insufficient available finance. In 1926 the research effort was reinvigorated by establishment of the Council for Scientific and Industrial Research (CSIR), which strengthened national science leadership and increased research funding. CSIR grew rapidly and achieved significant early successes. In 1949, further legislated changes included renaming the organisation as CSIRO. Notable developments by CSIRO have included the invention of atomic absorption spectroscopy, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Courier Dover Publications
Dover Publications, also known as Dover Books, is an American book publisher founded in 1941 by Hayward and Blanche Cirker. It primarily reissues books that are out of print from their original publishers. These are often, but not always, books in the public domain. The original published editions may be scarce or historically significant. Dover republishes these books, making them available at a significantly reduced cost. Classic reprints Dover reprints classic works of literature, classical sheet music, and public-domain images from the 18th and 19th centuries. Dover also publishes an extensive collection of mathematical, scientific, and engineering texts. It often targets its reprints at a niche market, such as woodworking. Starting in 2015, the company branched out into graphic novel reprints, overseen by Dover acquisitions editor and former comics writer and editor Drew Ford. Most Dover reprints are photo facsimiles of the originals, retaining the original pagination and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 156668 B
__NOTOC__ HD 156668 b is an extrasolar planet orbiting the star HD 156668 78.5 light-years away in the constellation Hercules. It has a minimum mass of 3.1 Earth masses. At the time of discovery it was the second least massive planet discovered by the radial velocity method after Gliese 581 e, subject to the mass/inclination degeneracy that affects radial velocity measurements. In addition to this, it has the lowest semi-amplitude, or the speed of the stellar wobble caused by planet's gravity tugging on the star determined by radial velocity, at 2.2 m/s. This planet was discovered on January 6, 2010; it is the 8th planet discovered in 2010 after the first five planets detected by Kepler Johannes Kepler (; ; 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws o ... on January 4 and two planets around HD ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimum Mass
In astronomy, minimum mass is the lower-bound calculated mass of observed objects such as planets, stars and binary systems, nebulae, and black holes. Minimum mass is a widely cited statistic for extrasolar planets detected by the radial velocity method or Doppler spectroscopy, and is determined using the binary mass function. This method reveals planets by measuring changes in the movement of stars in the line-of-sight, so the real orbital inclinations and true masses of the planets are generally unknown. This is a result of sin ''i'' degeneracy. If inclination ''i'' can be determined, the true mass can be obtained from the calculated minimum mass using the following relationship: M_\text = \frac Exoplanets Orientation of the transit to Earth Most stars will not have their planets lined up and orientated so that they eclipse over the center of the star and give the viewer on earth a perfect transit. It is for this reason that when we often are only able to extrapolate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doppler Spectroscopy
Doppler spectroscopy (also known as the radial-velocity method, or colloquially, the wobble method) is an indirect method for finding extrasolar planets and brown dwarfs from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star. 1,018 extrasolar planets (about 19.5% of the total) have been discovered using Doppler spectroscopy, as of November 2022. History Otto Struve proposed in 1952 the use of powerful spectrographs to detect distant planets. He described how a very large planet, as large as Jupiter, for example, would cause its parent star to wobble slightly as the two objects orbit around their center of mass. He predicted that the small Doppler shifts to the light emitted by the star, caused by its continuously varying radial velocity, would be detectable by the most sensitive spectrographs as tiny redshifts and blueshifts in the star's emission. However, the technology of the time produced radial-velocity meas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washington D
Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on Washington, D.C. * George Washington (1732–1799), the first president of the United States Washington may also refer to: Places England * Washington, Tyne and Wear, a town in the City of Sunderland metropolitan borough ** Washington Old Hall, ancestral home of the family of George Washington * Washington, West Sussex, a village and civil parish Greenland * Cape Washington, Greenland * Washington Land Philippines *New Washington, Aklan, a municipality *Washington, a barangay in Catarman, Northern Samar *Washington, a barangay in Escalante, Negros Occidental *Washington, a barangay in San Jacinto, Masbate *Washington, a barangay in Surigao City United States * Washington, Wisconsin (other) * Fort Washington (disambiguatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Super-Earth
A super-Earth is an extrasolar planet with a mass higher than Earth's, but substantially below those of the Solar System's ice giants, Uranus and Neptune, which are 14.5 and 17 times Earth's, respectively. The term "super-Earth" refers only to the mass of the planet, and so does not imply anything about the surface conditions or habitability. The alternative term "gas dwarfs" may be more accurate for those at the higher end of the mass scale, although "mini-Neptunes" is a more common term. Definition In general, super-Earths are defined by their masses, and the term does not imply temperatures, compositions, orbital properties, habitability, or environments. While sources generally agree on an upper bound of 10 Earth masses (~69% of the mass of Uranus, which is the Solar System's giant planet with the least mass), the lower bound varies from 1 or 1.9 to 5, with various other definitions appearing in the popular media. The term "super-Earth" is also used by astronomers to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star Catalogue
A star catalogue is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the years, and this article covers only some of the more frequently quoted ones. Star catalogues were compiled by many different ancient people, including the Babylonians, Greeks, Chinese, Persians, and Arabs. They were sometimes accompanied by a star chart for illustration. Most modern catalogues are available in electronic format and can be freely downloaded from space agencies' data centres. The largest is being compiled from the spacecraft Gaia and thus far has over a billion stars. Completeness and accuracy are described by the faintest limiting magnitude V (largest number) and the accuracy of the positions. Historical catalogues Ancient Near East From their existing records, it is known that the ancient Egyptians recorded the names of on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Córdoba, Argentina
Córdoba () is a city in central Argentina, in the foothills of the Punilla Valley, Sierras Chicas on the Primero River, Suquía River, about northwest of Buenos Aires. It is the capital of Córdoba Province, Argentina, Córdoba Province and the List of cities in Argentina by population, second most populous city in Argentina after Buenos Aires, with about 1.3 million inhabitants according to the 2010 census. It was founded on 6 July 1573 by Jerónimo Luis de Cabrera, who named it after Córdoba, Spain. It was one of the early Spanish colonial capitals of the region that is now Argentina (the oldest city is Santiago del Estero, founded in 1553). The National University of Córdoba is the oldest university of the country. It was founded in 1613 by the Society of Jesus, Jesuit Order. Because of this, Córdoba earned the nickname ''La Docta'' ("the learned"). Córdoba has many historical monuments preserved from Spanish colonization of the Americas, Spanish colonial rule, espe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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