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Ï… Orionis
Upsilon Orionis (υ Ori, υ Orionis) is a star in the constellation Orion. It has the traditional name ''Thabit'' or ''Tabit'' (ﺛﺎﺑﺖ, Arabic for "the endurer"), a name shared with Pi3 Orionis. It is a blue-white main sequence star of apparent magnitude 4.62 located over 1,300 light-years distant from the Solar System. It is a suspected Beta Cephei variable. Name Located south of Iota Orionis, Upsilon Orionis is one of two stars (the other is 29 Orionis) marking the top of Orion's right boot in Johann Bayer's ''Uranometria'' (1603). It was given the number 36 by John Flamsteed, while its proper name appears to be derived from the Arabic ''Al Thabit'' "the endurer". In his '' Star-Names and Their Meanings'' (1899), American amateur naturalist Richard Hinckley Allen noted that the name appeared on the star atlas ''Geography of the Heavens'', composed by Elijah Hinsdale Burritt, but its ultimate origin was unknown. Properties Since 1943, this star has been consis ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iota Orionis
Iota Orionis (ι Orionis, abbreviated ι Ori) is a Star system, multiple star system in the celestial equator, equatorial constellation of Orion (constellation), Orion the hunter. It is the eighth-brightest member of Orion with an Apparent magnitude, apparent visual magnitude of 2.77 and also the brightest member of the Asterism (astronomy), asterism known as Orion's Sword. It is a member of the NGC 1980 open cluster. From parallax measurements, it is located at a distance of roughly from the Sun. The system has three visible components designated Iota Orionis A, B and C. Iota Orionis A has also been resolved using speckle interferometry and is also a massive Binary star#Spectroscopic binaries, spectroscopic binary, with components Iota Orionis Aa1 (officially named Hatysa ), Aa2, and Ab. Nomenclature ''ι Orionis'' (Latinisation of names, Latinised to ''Iota Orionis'') is the system's Bayer designation. The designations of the three constituents as ''Iota Orionis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Year
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astronomical Union (IAU), a light-year is the distance that Speed of light, light travels in vacuum in one Julian year (astronomy), Julian year (365.25 days). Despite its inclusion of the word "year", the term should not be misinterpreted as a unit of time. The ''light-year'' is most often used when expressing distances to stars and other distances on a Galaxy, galactic scale, especially in public understanding of science, non-specialist contexts and popular science publications. The unit most commonly used in professional astronomy is the parsec (symbol: pc, about 3.26 light-years). Definitions As defined by the International Astronomical Union (IAU), the light-year is the product of the Julian year (astronomy), Julian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Parallax
Stellar parallax is the apparent shift of position (''parallax'') of any nearby star (or other object) against the background of distant stars. By extension, it is a method for determining the distance to the star through trigonometry, the stellar parallax method. Created by the different orbital positions of Earth, the extremely small observed shift is largest at time intervals of about six months, when Earth arrives at opposite sides of the Sun in its orbit, giving a baseline (the shortest side of the triangle made by a star to be observed and two positions of Earth) distance of about two astronomical units between observations. The parallax itself is considered to be half of this maximum, about equivalent to the observational shift that would occur due to the different positions of Earth and the Sun, a baseline of one astronomical unit (AU). Stellar parallax is so difficult to detect that its existence was the subject of much debate in astronomy for hundreds of years. Thomas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Association Of Variable Star Observers
The American Association of Variable Star Observers (AAVSO) is an international nonprofit organization. Founded in 1911, the organization focuses on coordinating, analyzing, publishing, and archiving variable star observations made largely by amateur astronomers. The AAVSO creates records that establish light curves depicting the variation in brightness of a star over time. The AAVSO makes these records available to professional astronomers, researchers, and educators. Professional astronomers do not have the resources to monitor every variable star. Hence, astronomy is one of the few sciences where amateurs can make significant contributions to research. In 2011, the 100th year of the AAVSO's existence, the twenty-millionth variable star observation was received into their database. The AAVSO International Database (AID) has stored over thirty-five million observations as of 2019. The organization receives nearly 1,000,000 observations annually from an estimated amount of 2,00 ... [...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 and distances of celestial objects on the sky. This permitted the first high-precision measurements of the intrinsic brightnesses, 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'' follow-up mission, '' Gaia'', was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slowly Pulsating B Star
A slowly pulsating B-type star (SPB), formerly known as a 53 Persei variable, is a type of pulsating variable star. They may also be termed a long-period pulsating B star (LPB). As the name implies, they are main sequence, main-sequence stars of B-type star, spectral type B2 to B9 (3 to 9 times as massive as the Sun) that pulsate with periods between approximately half a day and five days, however within this most member stars have been found to have multiple periods of oscillations. They display variability both in their light emission and in their spectral line profile. The variations in magnitude are generally smaller than 0.1 magnitudes, making it quite hard to observe variability with the naked eye in most cases. The variability increases with decreasing wavelength, thus they are more obviously variable in ultraviolet spectrum than visible light. Their pulsations are non-radial, that is, they vary in shape rather than volume; different parts of the star are expanding and contrac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactic O Star Catalogue
An astronomical catalogue is a list or tabulation of astronomical objects, typically grouped together because they share a common type, morphology, origin, means of detection, or method of discovery. Astronomical catalogs are usually the result of an astronomical survey of some kind. 0–9 * 0ES — Einstein Slew Survey, version 0See p. 20, X-ray sources in SIMBAD, J. M. Hameury, C. Motch, and M. Pakull, ''Bull. Inf. Centre Données Stellaires'' 47, pp. 19–20, . * 1A, 2A, 3A — Lists of X-ray sources from the Ariel V satellite * 1C — First Cambridge Catalogue of Radio Sources * 1ES — Einstein Slew Survey * 1FGL, 2FGL — Lists of gamma-ray sources from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope * 1RXH — ROSAT HRI Pointed Observations * 1RXS — ROSAT All-Sky Bright Source Catalogue, ROSAT All-Sky Survey Faint Source Catalog * 1SWASP — SuperWASP * 2A — see 1A * 2C — Second Cambridge Catalogue of Radio Sources * 2E — The Einstein Obs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morgan-Keenan Spectral Classification
In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grating into a spectrum exhibiting the Continuum (spectrum), rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary mainly due to the temperature of the photosphere, although in some cases there are true abundance differences. The ''spectral class'' of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature. Most stars are currently classified under the Morgan–Keenan (MK) system using the letters ''O'', ''B'', ''A'', ''F'', ''G'', ''K'', and ''M'', a sequence from the hottest (''O'' type) to the cool ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Hinckley Allen
''Star Names: Their Lore and Meaning'' is an 1899 book by Richard Hinckley Allen, that discusses the names of stars, constellations, and their histories. Background and authorship Richard Hinckley Allen (1838, near Buffalo, New York – 1908, Northampton, Massachusetts) was a youthful polymath with interests in "nature, astronomy, ornithology, and literature" whom his classmates described as "the walking encyclopedia"; after a college year spent at Yale, a pursuit abandoned because of problems with his eyesight, he traveled and then "joined his father’s export trade business". Allen's interest in astronomy, and in star names in particular, may have been stimulated by his coming across such a name with which he was unfamiliar, after which " spent many years researching astronomical nomenclature... primarily for personal enjoyment". With the encouragement of professors from Yale and Princeton, and from personal friends, Allen proceeded to publish the information he had gathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Their Lore And Meaning
In Modern English, ''they'' is a third-person pronoun relating to a grammatical subject. Morphology In Standard Modern English, ''they'' has five distinct word forms: * ''they'': the nominative (subjective) form * ''them'': the accusative (objective, called the 'oblique'.) and a non-standard determinative form. * ''their:'' the dependent genitive (possessive) form * ''theirs'': independent genitive form * ''themselves'': prototypical reflexive form * ''themself'': derivative reflexive form (nonstandard; now chiefly used instead of "himself or herself" as a reflexive epicenity for ''they'' in pronominal reference to a singular referent) History Old English had a single third-person pronoun , which had both singular and plural forms, and ''they'' wasn't among them. In or about the start of the 13th century, ''they'' was imported from a Scandinavian source (Old Norse , Old Danish, Old Swedish , ), in which it was a masculine plural demonstrative pronoun. It comes from P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Flamsteed
John Flamsteed (19 August 1646 – 31 December 1719) was an English astronomer and the first Astronomer Royal. His main achievements were the preparation of a 3,000-star catalogue, ''Catalogus Britannicus'', and a star atlas called '' Atlas Coelestis'', both published posthumously. He also made the first recorded observations of Uranus, although he mistakenly catalogued it as a star, and he laid the foundation stone for the Royal Greenwich Observatory. Life Flamsteed was born in Denby, Derbyshire, England, the only son of Stephen Flamsteed and his first wife, Mary Spadman. He was educated at the free school of Derby and at Derby School, in St Peter's Churchyard, Derby, near where his father carried on a malting business. At that time, most masters of the school were Puritans. Flamsteed had a solid knowledge of Latin, essential for reading the scientific literature of the day, and a love of history, leaving the school in May 1662.Birks, John L. (1999) ''John Flamsteed, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
