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HV 2112
HV 2112 is a cool luminous variable star in the Small Magellanic Cloud. Until 2018, it was considered to be the most likely candidate for a Thorne–Żytkow object, but it is now thought to be an asymptotic giant branch star. Discovery HV 2112 was first reported as a variable star in 1908, by Henrietta Leavitt. At the time it was identified as Harvard no. 2112. No period was given, but it was reported to be "probably long". The apparent magnitude, magnitude range was given as 13.7 to fainter than 16.5, from photographic plates. In 1966, analysis of Magellanic Cloud variable stars showed that HV 2112 had a photographic magnitude range from 13.0 to below 17.8. It was classified as a long-period variable, now known as a Mira variable, on the basis of its large amplitude and reasonably regular light variations, with a period of about 600 days. Possible object types AGB star HV 2112 had historically been treated as a very luminous asymptotic giant branch (AGB) star, a red gi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tucana
Tucana (The Toucan) is a constellation in the southern sky, named after the toucan, a South American bird. It is one of twelve constellations conceived in the late sixteenth century by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. Tucana first appeared on a celestial globe published in 1598 in Amsterdam by Plancius and Jodocus Hondius and was depicted in Johann Bayer's star atlas ''Uranometria'' of 1603. French explorer and astronomer Nicolas Louis de Lacaille gave its stars Bayer designations in 1756. The constellations Tucana, Grus (constellation), Grus, Phoenix (constellation), Phoenix and Pavo (constellation), Pavo are collectively known as the "Southern Birds". Tucana is not a prominent constellation as all of List of stars in Tucana, its stars are third magnitude or fainter; the brightest is Alpha Tucanae with an apparent magnitude, apparent visual magnitude of 2.87. Beta Tucanae is a star system with six member stars, while Ka ... [...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 current age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are formed from Gravitational collapse, 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 stellar core, 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 st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OGLE
Ogle may refer to: Places * Ogle County, Illinois, United States * Original name of Ashton, Illinois, a village * Ogle, Kentucky, United States, an unincorporated community * Ogle Township, Somerset County, Pennsylvania, United States * Ogle, Northumberland, England, a village * Ogle Castle in Northumberland, England * Glen Ogle, Scotland People * Ogle (surname) * Ogle family of Northumberland, England * Ogle Marbury (1882–1955), American jurist and politician, Chief Judge of the supreme court of Maryland * Ogle Moore (1801–1874), Irish Anglican priest Titles * Baron Ogle * Earl of Ogle Other uses * Ogle Airport Eugene F. Correia International Airport is located on the Atlantic Ocean coast of Guyana, east of the capital, Georgetown, Guyana, Georgetown, in the Demerara-Mahaica, Demerara-Mahaica region. In 2013, LIAT began scheduled passenger airline f ..., near Georgetown, Guyana * Ogle Design, a British design consultancy and onetime car maker * OGLE, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rubidium
Rubidium is a chemical element; it has Symbol (chemistry), symbol Rb and atomic number 37. It is a very soft, whitish-grey solid in the alkali metal group, similar to potassium and caesium. Rubidium is the first alkali metal in the group to have a density higher than Properties of water, water. On Earth, natural rubidium comprises two isotopes: 72% is a stable isotope Rb, and 28% is slightly radioactive Rb, with a half-life of 48.8 billion years – more than three times as long as the estimated age of the universe. German chemists Robert Bunsen and Gustav Kirchhoff discovered rubidium in 1861 by the newly developed technique, Atomic emission spectroscopy#Flame emission spectroscopy, flame spectroscopy. The name comes from the Latin word , meaning deep red, the color of its emission spectrum. Rubidium's compounds have various chemical and electronic applications. Rubidium metal is easily vaporized and has a convenient spectral absorption range, making it a frequent target for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molybdenum
Molybdenum is a chemical element; it has Symbol (chemistry), symbol Mo (from Neo-Latin ''molybdaenum'') and atomic number 42. The name derived from Ancient Greek ', meaning lead, since its ores were confused with lead ores. Molybdenum minerals have been known throughout history, but the element was discovered (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele. The metal was first isolated in 1781 by Peter Jacob Hjelm. Molybdenum does not occur naturally as a Native metal, free metal on Earth; in its minerals, it is found only in oxidation state, oxidized states. The free element, a silvery metal with a grey cast, has the List of elements by melting point, sixth-highest melting point of any element. It readily forms hard, stable carbides in alloys, and for this reason most of the world production of the element (about 80%) is used in steel alloys, including high-strength alloys and superalloys. Most molybdenum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium
Lithium (from , , ) is a chemical element; it has chemical symbol, symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard temperature and pressure, standard conditions, it is the least dense metal and the least dense solid element. Like all alkali metals, lithium is highly reactivity (chemistry), reactive and flammable, and must be stored in vacuum, inert atmosphere, or inert liquid such as purified kerosene or mineral oil. It exhibits a metallic luster (mineralogy), luster. It corrosion, corrodes quickly in air to a dull silvery gray, then black tarnish. It does not occur freely in nature, but occurs mainly as pegmatite, pegmatitic minerals, which were once the main source of lithium. Due to its solubility as an ion, it is present in ocean water and is commonly obtained from brines. Lithium metal is isolated electrolysis, electrolytically from a mixture of lithium chloride and potassium chloride. The Atomic nucleus, nucleus of the lithiu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Large Magellanic Cloud
The Large Magellanic Cloud (LMC) is a dwarf galaxy and satellite galaxy of the Milky Way. At a distance of around , the LMC is the second- or third-closest galaxy to the Milky Way, after the Sagittarius Dwarf Spheroidal Galaxy, Sagittarius Dwarf Spheroidal ( away) and the possible dwarf irregular galaxy called the Canis Major Overdensity. Based on the D25 isophote at the B-band (445 nm wavelength of light), the Large Magellanic Cloud is about across. It is roughly one-hundredth the mass of the Milky Way and is the fourth-largest galaxy in the Local Group, after the Andromeda Galaxy (M31), the Milky Way, and the Triangulum Galaxy (M33). The LMC is classified as a Magellanic spiral. It contains a stellar bar that is geometrically off-center, suggesting that it was once a barred dwarf spiral galaxy before its spiral arms were disrupted, likely by tidal interactions from the nearby Small Magellanic Cloud (SMC) and the Milky Way's gravity. The LMC is predicted to merge with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apache Point Observatory
The Apache Point Observatory (APO; obs. code: 705) is an astronomical observatory located in the Sacramento Mountains in Sunspot, New Mexico, United States, approximately south of Cloudcroft. The observatory is operated by New Mexico State University (NMSU) and owned by the Astrophysical Research Consortium (ARC). Access to the telescopes and buildings is private and restricted. History The ARC was formed in 1984 with the goal of building the 3.5 m telescope. It originally consisted of five institutions: New Mexico State University, University of Washington, University of Chicago, Princeton University, and Washington State University, some of which have since withdrawn. Several additional organizations have joined over time: Johns Hopkins University, University of Colorado, University of Virginia, Georgia State University, University of Oklahoma, University of Wyoming, and Brigham Young University. Funding for the 3.5 m and 0.5 m telescopes comes from the co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emily Levesque
Emily Levesque (born 1984) is an American astronomer, author, and associate professor in the Department of Astronomy at the University of Washington. She is known for her work on massive stars and using these stars to investigate galaxy formation. She is also the author of three books, including the 2020 popular science book ''The Last Stargazers: The Enduring Story of Astronomy's Vanishing Explorers''. Early life and education Levesque grew up in Taunton, Massachusetts. She received her undergraduate degree in physics at Massachusetts Institute of Technology in 2006, followed by a PhD in astronomy at the University of Hawaii in 2010. Academic career From 2010 to 2015, Levesque was a postdoctoral researcher at University of Colorado as an Einstein Fellow from 2010 to 2013, and then received a Hubble Fellowship from 2013 to 2015. She has been an assistant professor in the Department of Astronomy at the University of Washington since 2015. In 2015, Levesque, Rachel Bezanson, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magellan Telescopes
The Magellan Telescopes are a pair of optical telescopes located at Las Campanas Observatory in Chile. The two telescopes are named after the astronomer Walter Baade and the philanthropist Landon T. Clay. First light for the telescopes was on September 15, 2000 for the Baade, and September 7, 2002 for the Clay. A consortium consisting of the Carnegie Institution for Science, University of Arizona, Harvard University, the University of Michigan and the Massachusetts Institute of Technology built and operate the twin telescopes. The telescopes were named after the sixteenth-century Portuguese explorer Ferdinand Magellan. The Giant Magellan Telescope (GMT) is an extremely large telescope under construction, as part of the US Extremely Large Telescope Program. Current instruments on the Magellan Telescopes Baade telescope: * Inamori Magellan Areal Camera and Spectrograph (IMACS) * FourStar * Folded port InfraRed Echellette (FIRE) * Magellan Echellete (MagE) Clay telescope: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extrinsic S-type Star
An S-type star (or just S star) is a cool giant star with approximately equal quantities of carbon and oxygen in its atmosphere. The class was originally defined in 1922 by Paul Merrill for stars with unusual absorption lines and molecular bands now known to be due to s-process elements. The bands of zirconium monoxide (ZrO) are a defining feature of the S stars. The carbon stars have more carbon than oxygen in their atmospheres. In most stars, such as class M giants, the atmosphere is richer in oxygen than carbon and they are referred to as ''oxygen-rich stars''. S-type stars are intermediate between carbon stars and normal giants. They can be grouped into two classes: ''intrinsic'' S stars, which owe their spectra to convection of fusion products and s-process elements to the surface; and ''extrinsic'' S stars, which are formed through mass transfer in a binary system. The intrinsic S-type stars are on the most luminous portion of the asymptotic giant branch, a stage of their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radial Velocity
The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity onto the relative direction or line-of-sight (LOS) connecting the two points. The radial speed or range rate is the temporal rate of the distance or range between the two points. It is a signed scalar quantity, formulated as the scalar projection of the relative velocity vector onto the LOS direction. Equivalently, radial speed equals the norm of the radial velocity, modulo the sign. In astronomy, the point is usually taken to be the observer on Earth, so the radial velocity then denotes the speed with which the object moves away from the Earth (or approaches it, for a negative radial velocity). Formulation Given a differentiable vector \mathbf r \in \mathbb^3 defining the instantaneous relative position of a target with respe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
