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Pulsar Wind
A pulsar wind nebula (PWN, plural PWNe), sometimes called a plerion (derived from the Greek "πλήρης", ''pleres'', meaning "full"), is a type of nebula sometimes found inside the shell of a supernova remnant (SNR), powered by winds generated by a central pulsar. These nebulae were proposed as a class in 1976 as enhancements at radio wavelengths inside supernova remnants. They have since been found to be infrared, optical, millimetre, X-ray and gamma ray sources. Evolution of pulsar wind nebulae Pulsar wind nebulae evolve through various phases. New pulsar wind nebulae appear soon after a pulsar's creation, and typically sit inside a supernova remnant, for example the Crab Nebula, or the nebula within the large Vela Supernova Remnant. As the pulsar wind nebula ages, the supernova remnant dissipates and disappears. Over time, pulsar wind nebulae may become bow-shock nebulae surrounding millisecond or slowly rotating pulsars. Properties of pulsar wind nebulae Pulsar winds a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vela Pulsar Jet
Vela or Velas may refer to: Astronomy * Vela (constellation), a constellation in the southern sky (the Sails) ** Vela (Chinese astronomy) ** Vela Pulsar ** Vela X-1, a pulsing, eclipsing high-mass X-ray binary system Places * Vela Bluff, Antarctica * Vela, Dolj, Romania * Vela (Ilidža – Sarajevo), Bosnia and Herzegovina * Velas, Maharashtra, India Ships * '' CMA CGM Vela'', a container ship in service since 2008 * USNS ''Vela'' (T-AK-89), US Army port repair ship * ''Vela''-class submarine, of the Indian Navy ** INS ''Vela'' (S40), in service 1973–2010 Technology * Project Vela, a system developed by the United States to monitor compliance with the Partial Test Ban Treaty ** Vela (satellite), a series of satellites launched by the United States to monitor nuclear testing *** Vela incident, an international incident, in which a Vela satellite is thought to possibly have observed a nuclear test * Versatile Laboratory Aid (VELA), a data logging tool used in educati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchrotron Radiation
Synchrotron radiation (also known as magnetobremsstrahlung) is the electromagnetic radiation emitted when relativistic charged particles are subject to an acceleration perpendicular to their velocity (). It is produced artificially in some types of particle accelerators or naturally by fast electrons moving through magnetic fields. The radiation produced in this way has a characteristic polarization, and the frequencies generated can range over a large portion of the electromagnetic spectrum. Synchrotron radiation is similar to bremsstrahlung radiation, which is emitted by a charged particle when the acceleration is parallel to the direction of motion. The general term for radiation emitted by particles in a magnetic field is ''gyromagnetic radiation'', for which synchrotron radiation is the ultra-relativistic special case. Radiation emitted by charged particles moving non-relativistically in a magnetic field is called cyclotron emission. For particles in the mildly relativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactic Superwind
A galactic superwind, or just galactic wind, is a high velocity stellar wind emanating from either newly formed massive stars, spiral density waves, or as the result of the effects of supermassive black holes. They are normally observed in Starburst galaxy, starburst galaxies. Description Galactic winds are strong stellar winds made up of charged particles, ejecta, and varying amounts of hot and cool gas, interacting with enough force that the ejecta's kinetic energy is converted to thermal energy. The resulting effect is a massive gust of rapidly expanding super-heated gases that can span the length of a galaxy. In galaxies with active Active galactic nucleus, galactic nuclei, galactic winds can also be driven by the effects of super-massive black holes. Galactic winds are considered an important function in the evolution of a galaxy. The winds cause an outflow of gas and other material into the galactic halo, halo of a galaxy, while also facilitating the spread of metallicity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colliding-wind Binary
A colliding-wind binary is a binary star system in which the two members are massive stars that emit powerful, radiatively-driven stellar winds. The location where these two winds collide produces a strong shock front that can cause radio, X-ray and possibly synchrotron radiation emission. Wind compression in the bow shock region between the two stellar winds allows dust formation. When this dust streams away from the orbiting pair, it can form a pinwheel nebula of spiraling dust. Such pinwheels have been observed in the Quintuplet Cluster. The archetype of such a colliding-wind binary system is WR 140 (HD 193793), which consists of a 20 solar mass () Wolf-Rayet star orbiting about a , spectral class O4–5 main sequence star every 7.9 years. The high orbital eccentricity of the pair allows astronomers to observe changes in the colliding wind region as their separation varies. Another prominent example of a colliding-wind binary is thought to be Eta Carinae, one of the most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar-wind Bubble
A stellar-wind bubble is a cavity light-years across filled with hot gas blown into the interstellar medium by the high-velocity (several thousand km/s) stellar wind from a single massive star of type O or B. Weaker stellar winds also blow bubble structures, which are also called astrospheres. The heliosphere blown by the solar wind, within which all the major planets of the Solar System are embedded, is a small example of a stellar-wind bubble. Stellar-wind bubbles have a two-shock structure. The freely-expanding stellar wind hits an inner termination shock, where its kinetic energy is thermalized, producing 106 K, X-ray-emitting plasma. The hot, high-pressure, shocked wind expands, driving a shock into the surrounding interstellar gas. If the surrounding gas is dense enough (number densities n > 0.1 \mbox^ or so), the swept-up gas radiatively cools far faster than the hot interior, forming a thin, relatively dense shell around the hot, shocked wind. See also * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetary Wind
Atmospheric escape is the loss of planetary Atmosphere, atmospheric gases to outer space. A number of different mechanisms can be responsible for atmospheric escape; these processes can be divided into thermal escape, non-thermal (or suprathermal) escape, and impact erosion. The relative importance of each loss process depends on the planet's escape velocity, its atmosphere composition, and its distance from its star. Escape occurs when molecular kinetic energy overcomes gravitational energy; in other words, a molecule can escape when it is moving faster than the escape velocity of its planet. Categorizing the rate of atmospheric escape in exoplanets is necessary to determining whether an atmosphere persists, and so the exoplanet's Circumstellar habitable zone, habitability and likelihood of life. Thermal escape mechanisms Thermal escape occurs if the molecular velocity due to thermal energy is sufficiently high. Thermal escape happens at all scales, from the molecular level (Jean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Wind
The solar wind is a stream of charged particles released from the Sun's outermost atmospheric layer, the Stellar corona, corona. This Plasma (physics), plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the solar wind plasma also includes a mixture of particle species found in the solar plasma: trace amounts of heavy ions and atomic nuclei of Chemical element, elements such as carbon, nitrogen, oxygen, neon, magnesium, silicon, sulfur, and iron. There are also rarer traces of some other nuclei and isotopes such as phosphorus, titanium, chromium, and nickel's isotopes 58Ni, 60Ni, and 62Ni. Superimposed with the solar-wind plasma is the interplanetary magnetic field. The solar wind varies in density, temperature and speed over time and over Solar coordinate systems#Heliographic, solar latitude and longitude. Its particles can escape the Sun's gravity because of their high energy resulting from the high temperature of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Wind
A stellar wind is a flow of gas ejected from the stellar atmosphere, upper atmosphere of a star. It is distinguished from the bipolar outflows characteristic of young stars by being less collimated, although stellar winds are not generally spherically symmetric. Different stellar classification, types of stars have different types of stellar winds. Post-main sequence, main-sequence stars nearing the ends of their lives often eject large quantities of mass in massive ( \scriptstyle \dot > 10^ solar masses per year), slow (v = 10 km/s) winds. These include red giants and Red supergiant, supergiants, and asymptotic giant branch stars. These winds are understood to be driven by radiation pressure on Cosmic dust, dust condensing in the upper atmosphere of the stars. Young T Tauri stars often have very powerful stellar winds. Massive stars of stellar classification, types O star, O and B V star, B have stellar winds with lower mass loss rates (\scriptstyle \dot 1–2000 km ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmic Wind
Cosmic wind is a powerful cosmic stream of charged particles that can push interstellar dust clouds of low density into intergalactic space. Although it easily pushes low density gas and dust clouds, it cannot easily push high density clouds. As the cosmic winds start to push the clouds, they start to separate and start looking like taffy being pulled apart. It has a primary composition of photons ejected from large stars and sometimes thermal energy from exploding stars. It can be caused by orbital motion of gas in the cluster of a galaxy, or can be ejected from a black hole. Because new stars and planets form from gases, the cosmic winds that push the gases away are preventing new stars from forming and are ultimately playing a role in galaxy evolution. Description These winds come from the thermal expansion of galactic halos in O and B stars and are further increased by cosmic rays, which shoot out and help push gas out of the halo and disk of its galaxy. In these supern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G292
G, or g, is the seventh letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages, and others worldwide. Its name in English is ''gee'' (pronounced ), plural ''gees''. The lowercase version can be written in two forms: the single-storey (sometimes "opentail") and the double-storey (sometimes "looptail") . The former is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children. History The evolution of the Latin alphabet's G can be traced back to the Latin alphabet's predecessor, the Greek alphabet. The voiced velar stop was represented by the third letter of the Greek alphabet, gamma (Γ), which was later adopted by the Etruscan language. Latin then borrowed this "rounded form" of gamma, C, to represent the same sound in words such as ''recei'', which was likely an early dative form of '' rex'', meaning "king", as found in an "early Latin inscription." Over time, howe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3C 58
3C 58 or 3C58 is a pulsar (designation PSR J0205+6449) and supernova remnant (pulsar wind nebula) within the Milky Way. The object is listed as No. 58 in the Third Cambridge Catalogue of Radio Sources. It is located 2° northeast of ε Cassiopeiae and is estimated to be 10,000 light-years away. Its rotation period is 65.7 ms (so PSR J0205+6449 does not belong to the class of millisecond pulsars). The pulsar is notable for its very high rate of cooling, which is unexplained by standard models of neutron star formation. It is hypothesized that extreme conditions in the star's interior cause a high neutrino flux, which carries away the energy so that the star cools. 3C 58 has been proposed as a possible quark star (or strange star). The age of the 3C 58 remnant has been measured by a number of independent methods. The proper motion of the expanding optical shell of 3C 58 has been measured three times, always with an indicated age of around 3500 years, with thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teraelectronvolt
In physics, an electronvolt (symbol eV), also written electron-volt and electron volt, is the measure of an amount of kinetic energy gained by a single electron accelerating through an electric potential difference of one volt in vacuum. When used as a unit of energy, the numerical value of 1 eV in joules (symbol J) is equal to the numerical value of the charge of an electron in coulombs (symbol C). Under the 2019 revision of the SI, this sets 1 eV equal to the exact value Historically, the electronvolt was devised as a standard unit of measure through its usefulness in electrostatic particle accelerator sciences, because a particle with electric charge ''q'' gains an energy after passing through a voltage of ''V''. Definition and use An electronvolt is the amount of energy gained or lost by a single electron when it moves through an electric potential difference of one volt. Hence, it has a value of one volt, which is , multiplied by the elementary charge Therefore, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
