An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 716
double vision
  دوبینی   
dobini (#)

Fr.: vision double   

Same as → diplopia.

double; → vision.

double white dwarf
  سفیدکوتوله‌ی ِ دوتایی   
sefid kutule-ye dotâyi

Fr.: naine blanche double   

A → double-lined binary with two → white dwarf components. Short-period double white dwarfs can lose → orbital angular momentum by emitting → gravitational radiation and if the total mass of the binary exceeds the → Chandrasekhar limit, their eventual → merger might produce a → Type Ia supernova.

double; → white; → dwarf.

double-degenerate binary system
  راژمان ِ درین ِ دوبار واگن   
râžmân-e dorin-e dobâr vâgen

Fr.: système binaire doublement dégénéré   

A system of evolved → binary stars in which both → components have ejected their envelopes and evolve toward → white dwarf stage. So far a half dozen double-degenerate → binary systems are known, for example Henize 2-248 (M. Santander-Garcia et al., 2015, 518, 5).

double; → degenerate; → binary; → system.

double-diffusive convection
  همبز ِ دوپخشی   
hambaz-e do paxši

Fr.:   

An instability involving two layers of fluid with opposite gradients of properties. Same as → fingering instability. See also → salt finger. Double-diffusive instabilities commonly occur in any astrophysical fluid that is stable according to the → Ledoux criterion, as long as the entropy and chemical stratifications have opposing contributions to the dynamical stability of the system. They drive weak forms of convection, and can cause substantial heat and compositional → mixing. Two cases can be distinguished. In fingering convection, entropy is stably stratified (∇ - ∇ad < 0), but chemical composition is unstably stratified (∇μ < 0); it is often referred to as → thermohaline convection by analogy with the oceanographic context in which the instability was first discovered. In oscillatory double-diffusive convection, entropy is unstably stratified (∇ - ∇ad > 0), but chemical composition is stably stratified (∇μ > 0); it is related to semiconvection, but can occur even when the → opacity is independent of composition (P. Garaud, 2014, arXiv:1401.0928).

double;→ diffusive; → system.

double-lined binary
  دورین ِ دوخطه   
dorin-e doxatté

Fr.: binaire à double raies   

A → spectroscopic binary in which the → spectral lines of both stars are seen and the lines are alternatively double and single. Same as → SB2 binary. See also: → single-lined binary.

double; → line; → binary

double-lined eclipsing binary
  دورین ِ گرفتی ِ دوخطه   
dorin-e gerefti-ye doxatté

Fr.: binaire à éclipse à double raies   

A → double-lined spectroscopic binary whose → light curve is typical of an → eclipsing binary.

double; → line; → eclipsing; → binary.

double-lined spectroscopic binary
  درین ِ دوخطه‌ی ِ بیناب‌نماییک   
dorin-e doxatte-ye binâbnemâyik

Fr.: binaire spectroscopique à double raies   

Same as → double-lined binary.

double; → line; → spectroscopic; → binary.

double-lobed radio source
  خن ِ رادیویی با لپ ِ دوتایی   
xan-e râdioyi bâ lap-e dotâyi

Fr.: radio source à double lobe   

A → galaxy that emits radio energy from two regions located on opposite sides of the galaxy.

double; → lobe; → radio; → source.

double-slit experiment
  آزمایش ِ شکاف ِ دوتایی   
âzmâyeš-e šekâf-e dotâyi (#)

Fr.: expérience de double fente   

An experiment of → diffraction and → interference of two light beams using a → double slit; → Young's experiment.

double; → slit; → experiment.

doublet
  دوتایه   
dotâyé

Fr.: doublet   

A pair of forbidden spectral lines of the same atom arising from a common upper excitation level, for example [O III] λ 5007 and [O III] λ 4959, [N II] λ 6584 and [N II] λ 6548, and [S II] λ 6717, [S II] λ 6731.
A pair of associated lines arising from transitions having a common lower energy level in a spectrum characteristic of the alkali metals.

From O.Fr. doublet, from → double + -et diminutive suffix.

Dotâyé, from dotâdouble + -(y)é nuance suffix.

doubly
  دوبار-، دو-، دوتایی   
dobâr-, dv-, dotâyi

Fr.: double, à ~   

1) To a double measure or degree.
2) In a double manner. → doubly convex, → doubly ionized, → doubly refracting crystal.

double; → -ly (; → twice).

doubly convex
  دو-کوژ   
do-kuž

Fr.: double-convexe   

Describing a → lens which is → convex on both sides.

doubly; → convex.

doubly ionized
  دوبار یونیده   
dobâr yonidé (#)

Fr.: deux fois ionisé   

An atom that has lost two of its external electrons, for example O++ ([O III]).

doubly; → ionized.

doubly refracting crystal
  بلور ِ شکست ِ دوتایی   
bolur-e šakst-e dotâyi

Fr.: cristal à double réfraction   

A → transparent → crystalline substance (such as calcite, quartz, and tourmaline) that is → anisotropic relative to the → speed of light. A ray incident normally on such crystals is broken up into two rays in traversing the crystal, → ordinary ray and → extraordinary ray.

doubly; → refracting; → crystal.

doubt
  گمان، شک، دودلی   
gomân (#), šakk (#), dodeli (#),

Fr.: doute   

1) A feeling of uncertainty about the truth, reality, or nature of something. → skepticism.
2) To be uncertain about; consider questionable or unlikely; hesitate to believe (Dictionary.com).

M.E. douten, from O.Fr. douter "doubt, be doubtful," from L. dubitare "to doubt, question, hesitate" (related to dubius "uncertain"), from duo, "→ two," + habere "have, hold," with a sense of "of having two minds, undecided between two things;" cf. Pers. dodeli, as below.

Gomân, from Mid.Pers. gumân "doubt;" ultimately from Proto-Ir. *ui-man-, from suffixed *man- "to think," → idea.
Šakk, loan from Ar.
Dodeli, literally "having two minds," from do, → two, + del, → heart (also meaning "soul, spirit, will, desire, courage, mind"); cf. Sogdian δβanā (from *dwa-nā), Ger. Zweifel, and L. dubius, as above.

down
  پایین، فرو   
pâyin (#), foru

Fr.: en bas, vers le bas   

Toward or in a lower physical position.
See also: → download, → downgrade, → upload, → downsizing, → meltdown, → overload, → spin-down, → top-down structure formation.

M.E. doun, from O.E. dune "downward," short for adune, ofdune, from a-, of "off, from" + dune "hill."

Pâyin "bottom, below; at the foot of," from pâ(y) "foot; step;" Mid.Pers. pâd, pây; Av. pad- "foot;" cf. Skt. pat; Gk. pos, genitive podos; L. pes, genitive pedis; E. foot; Ger. Fuss; Fr. pied; PIE *pod-/*ped-.
Foru "down, downward; below, under, beneath; low," Mid.Pers. frôt "down, downward;" O.Pers. fravata "forward, downward;" Skt. pravát- "a sloping path, the slope of a mountain."

downgrade
  فرود-پداک، فرود-پداکیدن   
forud-padâk, forud-padâkidan

Fr.: déclasser, dévaloriser   

1) A downward slope, especially of a road.
2) To assign to a lower status; to minimize the importance of (Dictionary.com).

down; → grade.

download
  ۱) بارگرفتن؛ ۲) بارگیری   
1) bârgereftan; 2) bârgiri (#)

Fr.: 1) télécharger; 2) téléchargement   

1) To transfer data from any other computer to one's computer.
2) The act of downloading.

down; → load.

Bârgereftan, literally "to take load," from bâr, → load, + gereftan "to take," → receiver; bârgiri, verbal noun of bârgereftan.

downsizing
  بزرگ-به-کوچک   
bozorg-bé-kucak

Fr.:   

A scenario of galaxy formation whereby massive galaxies formed earlier in the history of the → Universe (i.e. at high → redshifts) and completed their → star formation process more rapidly than low-mass galaxies. This scenario contrasts with what might be expected from simple → hierarchical structure formation scenarios, which predict that large galaxies formed in more recent times through the → merging of small galaxies.

Downsizing, first suggested by Cowie et al. (1996, AJ 112, 839), from downsize (v.), is a new sense for this term. Its current main meaning in non astrophysical contexts is "to make in a smaller size, or become smaller in size (in particular in economic vocabulary, by reductions in personnel)," from → down + → size.

Bozorg-bé-kucak, literally "large to small," from bozorg, → large, + "to" + kucak, → small.

downstream
  فروداب   
forudâb (#)

Fr.: en aval   

1) With or in the direction of the current of a stream. → upstream.
2) Of or pertaining to the latter part of a process or system.

down; → stream.

Forud, → incidence; water, → water.

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