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BI 253
BI 253 is an O2V star in the Large Magellanic Cloud and is a primary standard of the O2 type. It is one of the hottest main-sequence stars known and one of the most-massive and most-luminous stars known. Discovery BI 253 was first catalogued in 1975 as the 253rd of 272 likely O and early B stars in the Large Magellanic Cloud. In 1995, the spectral type was analysed to be O3 V, the earliest type defined at that time. When the classification of the earliest type O stars was refined in 2002, the complete lack of neutral helium or doubly ionised nitrogen lines in the spectrum led to BI 253 being placed in a new O2 V class. It was given a ((f*)) qualifier because of the very weak emission lines of helium and nitrogen. The most recent published data gives a spectral type of O2V-III(n)((f*)), although it is unclear whether this is due to higher quality spectra or an actual change in the spectrum. BI 253 has been identified as a runaway star because of its relatively is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
30 Doradus
The Tarantula Nebula (also known as 30 Doradus) is a large H II region in the Large Magellanic Cloud (LMC), forming its south-east corner (from Earth's perspective). Discovery The Tarantula Nebula was observed by Nicolas-Louis de Lacaille during an expedition to the Cape of Good Hope between 1751 and 1753. He catalogued it as the second of the "Nebulae of the First Class", "Nebulosities not accompanied by any star visible in the telescope of two feet". It was described as a diffuse nebula 20' across. Johann Bode included the Tarantula in his 1801 ''Uranographia'' star atlas and listed it in the accompanying ''Allgemeine Beschreibung und Nachweisung der Gestirne'' catalogue as number 30 in the constellation "Xiphias or Dorado". Instead of being given a stellar magnitude, it was noted to be nebulous. The name Tarantula Nebula arose in the mid 20th century from its appearance in deep photographic exposures. 30 Doradus has often been treated as the designation of a star, or of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2MASS Objects
Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementary particles, theoretically with the same amount of matter, have nonetheless different masses. Mass in modern physics has multiple definitions which are conceptually distinct, but physically equivalent. Mass can be experimentally defined as a measure of the body's inertia, meaning the resistance to acceleration (change of velocity) when a net force is applied. The object's mass also determines the strength of its gravitational attraction to other bodies. The SI base unit of mass is the kilogram (kg). In physics, mass is not the same as weight, even though mass is often determined by measuring the object's weight using a spring scale, rather than balance scale comparing it directly with known masses. An object on the Moon would weigh less t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Runaway Stars
In astronomy, stellar kinematics is the observational study or measurement of the kinematics or motions of stars through space. Stellar kinematics encompasses the measurement of stellar velocities in the Milky Way and its satellites as well as the internal kinematics of more distant galaxies. Measurement of the kinematics of stars in different subcomponents of the Milky Way including the thin disk, the thick disk, the bulge, and the stellar halo provides important information about the formation and evolutionary history of our Galaxy. Kinematic measurements can also identify exotic phenomena such as hypervelocity stars escaping from the Milky Way, which are interpreted as the result of gravitational encounters of binary stars with the supermassive black hole at the Galactic Center. Stellar kinematics is related to but distinct from the subject of stellar dynamics, which involves the theoretical study or modeling of the motions of stars under the influence of gravity. Stellar-dyn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extragalactic Stars
Extragalactic astronomy is the branch of astronomy concerned with objects outside the Milky Way galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy. The closest objects in extragalactic astronomy include the galaxies of the Local Group, which are close enough to allow very detailed analyses of their contents (e.g. supernova remnants, stellar associations). As instrumentation has improved, distant objects can now be examined in more detail and so extragalactic astronomy includes objects at nearly the edge of the observable universe. Research into distant galaxies (outside of our local group) is valuable for studying aspects of the universe such as galaxy evolution and Active Galactic Nuclei (AGN) which give insight into physical phenomena (e.g. super massive black hole accretion and the presence of dark matter). It is through extragalactic astronomy that astronomers and physicists are able to study the effects of General ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorado (constellation)
Dorado () is a constellation in the southern sky. It was named in the late 16th century and is now one of the 88 modern constellations. Its name refers to the dolphinfish (''Coryphaena hippurus''), which is known as ''dorado'' in Spanish, although it has also been depicted as a swordfish. Dorado contains most of the Large Magellanic Cloud, the remainder being in the constellation Mensa. The South Ecliptic pole also lies within this constellation. Even though the name Dorado is not Latin but Spanish, astronomers give it the Latin genitive form ''Doradus'' when naming its stars; it is treated (like the adjacent asterism Argo Navis) as a feminine proper name of Greek origin ending in -ō (like ''Io'' or ''Callisto'' or ''Argo''), which have a genitive ending ''-ūs''. History Dorado was one of twelve constellations named by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. It appeared: * On a celestial globe published in 1597 (or 1598 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stars In The Large Magellanic Cloud
A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth make them appear as fixed points of light. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. The observable universe contains an estimated to stars. Only about 4,000 of these stars are visible to the naked eye, all within the Milky Way galaxy. A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Its total mass is the main factor determining its evolution and eventual fate. A star shines for most of its active life due ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminosity Class
In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the 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 coolest (''M'' type). Each letter class is then subdivided ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supergiant
Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8. The temperature range of supergiant stars spans from about 3,400 K to over 20,000 K. Definition The title supergiant, as applied to a star, does not have a single concrete definition. The term ''giant star'' was first coined by Hertzsprung when it became apparent that the majority of stars fell into two distinct regions of the Hertzsprung–Russell diagram. One region contained larger and more luminous stars of spectral types A to M and received the name ''giant''. Subsequently, as they lacked any measurable parallax, it became apparent that some of these stars were significantly larger and more luminous than the bulk, and the term ''super-giant'' arose, quickly adopted as ''supergiant''. Spectral luminosity class Supergiant stars can be identified on the basis of thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giant Star
A giant star is a star with substantially larger radius and luminosity than a main sequence, main-sequence (or ''dwarf'') star of the same effective temperature, surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Press, 2002. . They lie above the main sequence (luminosity class V in the Spectral classification#Yerkes spectral classification, Yerkes spectral classification) on the Hertzsprung–Russell diagram and correspond to luminosity classes II and III.giant, entry in ''The Facts on File Dictionary of Astronomy'', ed. John Daintith and William Gould, New York: Facts On File, Inc., 5th ed., 2006. . The terms ''giant'' and ''dwarf'' were coined for stars of quite different luminosity despite similar temperature or spectral type by Ejnar Hertzsprung about 1905. Giant stars have radii up to a few hundred times the solar radii, Sun and luminosities between 10 and a few thousand times that of the Sun. Stars still mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ZAMS
Zams is a municipality in the district of Landeck in the Austrian state of Tyrol. Geography The Inn River runs through Zams, which is situated in the river's basin together with its neighbour town Landeck. The geographical location is . Here, the old roads coming from Vinschgau, Engadin, Bavaria, and Lake Constance cross. At the bridge over the Inn, tolls were demanded from trade wagons as early as the Middle Ages. The municipality comprises two villages, Zams and the much smaller Zammerberg. Local places Zams: Lötz, Rease, Oberdorf, Engere, Oberreit, Unterreit, Siedlung, Riefe Zammerberg: Falterschein, Grist, Kronburg, Lahnbach, Rifenal, Schwaighof, Tatschhof, Anreit Ausserfern: Madau Neighbour municipalities Bach, Fließ, Flirsch, Gramais, Grins, Imst, Kaisers, Landeck, Schönwies, Stanz bei Landeck, Strengen, Wenns History Zams has been populated since pre-Christian times, though the first known use of the name (as "Zamis") is from 1150. While Zams has often enjoyed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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