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elliptic aberration birâheš-e biyzigun Fr.: aberration elliptique That part of → annual aberration proportional to the → eccentricity of the Earth's orbit. → elliptic; → aberration. |
emigration zomužeš Fr.: émigration An act or instance of emigrating; a body of emigrants; emigrants collectively. Verbal noun of → emigrate. |
energy generation equation hamugeš-e âzâneš-e kâruž Fr.: équation de génération d'énergie Of a stellar → nuclear fusion, the equation describing the → energy generation rate as a function of → density and → temperature. → energy; → generation; → equation. |
energy generation rate nerx-e âzâneš-e kâruž Fr.: taux de génération d'énergie Of a stellar → nuclear fusion, the energy produced per unit mass per unit time, usually denoted ε (erg g^{-1}s^{-1}). The general form of the energy generation equation is: ε = ε_{0}ρ^{λ}T^{ν}, where ε_{0}, ρ, and λ are constants over some efficiently restricted range of → temperature T, → density ρ, and → chemical composition. The temperature exponent ν is about 4, 15, and 40 for → proton-proton chain, → CNO cycle, and → triple alpha process, respectively. → energy; → generation; → rate. |
evaporation boxâreš Fr.: évaporation The physical process by which a liquid is transformed to the gaseous state, usually by means of heat; the opposite of → condensation. Also called vaporization. From L. evaporationem (nom. evaporatio), from evaporare "to disperse in vapor," from → ex- "out" + → vapor "steam." Boxârš, verbal noun of boxâridan "to evaporate," from boxâr, → vapor. |
exploration puyeš (#) Fr.: exploration 1) An act or instance of exploring or investigating; examination. Verbal noun of → explore. |
extreme mass ratio inspiral (EMRI) forupicé bâ vâbar-e ostom-e jerm Fr.: orbite plongeante d'un trou noir binaire, au rapport de masse extrême A compact stellar remnant (e.g., a → white dwarf, → neutron star, or → black hole) that undergoes → inspiral into a much more massive object (→ supermassive black hole found → galactic centers). EMRIs are potential sources of low-frequency → gravitational waves. Predictions of the EMRI event rates span a wide range, from ~ 10^{-9} to 10^{-6} yr^{-1} per galaxy (Merritt et al. 2011, Physical Review D 84, 044024). See also → resonant relaxation. |
federation hiâyveš Fr.: fédération 1) The act of federating or uniting in a league. Verbal noun of → federate. |
flux calibration kabizeš-e šârr Fr.: calibration de flux The → calibration of the flux received by a detector in terms of absolute units. → flux; → calibration. |
focal ratio vâbar-e kânuni Fr.: rapport focal The ratio of the → focal length of a reflecting surface or lens to its effective diameter, i.e. to its → aperture. The smaller the focal ratio, the smaller the image scale and the more luminous the image for a given aperture. |
gas-to-dust ratio vâbar-e gâz bé qobâr Fr.: rapport gaz/poussière The mass ratio of gas to dust. It amounts to approximately 100 in the → interstellar medium, but may vary in → molecular clouds and → circumstellar disks due to dust → grain evaporation, → dust settling, → condensation of gas, etc. The gas-to-dust ratio depends on the → metallicity. It is larger in galaxies with lower metallicity. |
generation âzâneš Fr.: génération 1) A coming into being. Verbal noun of → generate. |
geometrical libration roxgard-e hendesi (#) Fr.: libration géométrique Libration resulting from changes in the location of the observer with respect to body. More specifically, a lunar libration motion that results from the Earth based observer seeing the Moon from different directions at different times. There are three types of geometrical libration: → libration in longitude, → libration in latitude, and → diurnal libration. See also → physical libration. |
golden ratio vâbar-e zarrin Fr.: nombre d'or If a line segment is divided into a larger subsegment (a) and a smaller subsegment (b), when the larger subsegment is related to the smaller exactly as the whole segment is related to the larger segment, i.e. a/b = (a + b)/a. The golden ratio, a/b is usually represented by the Greek letter φ. It is also known as the divine ratio, the golden mean, the → golden number, and the golden section. It was believed by Greek mathematicians that a rectangle whose sides were in this proportion was the most pleasing to the eye. Similarly, the ratio of the radius to the side of a regular → decagon has this proportion. The numerical value of the golden ratio, given by the positive solution of the equation φ^{2} - φ - 1 = 0, is φ = (1/2)(1 + √5), approximately 1.618033989. The golden ratio is an → irrational number. It is closely related to the → Fibonacci sequence. |
grain evaporation boxâreš-e dâné Fr.: évaporation des grains Conversion of dust grains into smaller grains due to high environmental temperatures. → grain; → evaporation. |
gravitational acceleration šetâb-e gerâneši (#) Fr.: accélération gravitationnelle The acceleration caused by the force of gravity. At the Earth's surface it is determined by the distance of the object form the center of the Earth: g = GM/R^{2}, where G is the → gravitational constant, and M and R are the Earth's mass and radius respectively. It is approximately equal to 9.8 m s^{-2}. The value varies slightly with latitude and elevation. Also known as the → acceleration of gravity. → gravitational; → acceleration. |
helium-argon calibration kabizeš-e heliyom-ârgon Fr.: calibration hélium-argon A wavelength calibration of astronomical spectra using a helium-argon light source. → helium; → argon; → calibration. |
HESS collaboration hamkâri-ye HESS Fr.: collaboration HESS → High Energy Stereoscopic System (H.E.S.S.). → H.E.S.S.; → collaboration. |
hydration hidreš, âbeš (#) Fr.: hydratation The process of combining with → water. Verbal noun of → hydrate. |
image restoration bâzsâzi-ye vine, ~ tasvir (#) Fr.: restauration d'image The process by virtue of which the original image can be created by removing the blurring and the noise that occur during image formation. → image; → restoration. |
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