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: 457
heterodyne receiver
  گیرنده‌ی ِ هترودینی   
girande-ye heterodini (#)

Fr.: récepteur hétérodyne   

superheterodyne receiver.

heterodyne; → receiver.

heterodyne technique
  تشنیک ِ هترودین   
tašnik-e heterodin

Fr.: technique hétérodyne   

superheterodyne technique.

heterodyne; → technique.

heterogeneity
  دگرگنی   
degargeni

Fr.: hétérogénéité   

The quality or state of being → heterogeneous. See also → homogeneity, → inhomogeneity.

Noun from → heterogeneous.

heterogeneous
  دگرگن   
degargen

Fr.: hétérogène   

1) Composed of parts of different kinds; having widely dissimilar elements or constituents. See also → homogeneous, → inhomogeneous.
2) Chemistry: A mixture that does not have uniform composition and properties throughout; composed of different substances or the same substance in different phases.

hetero- + -genous, → homogeneous.

heuristic
  یافتیک   
yâftik

Fr.: heuristique   

Methodology, Math.: Pertaining to a method of analyzing outcome through comparison to previously recognized patterns in the absence of an → algorithm for formal proof.

From L. heuristicus (from Gk. heuretikos "inventive," related to heuriskein "to find," from heur-) + -isticus, → -ic.

Yâftik, from yâft past tense of yâftan, yâb- "to → find" + -ik, → -ic.

hexa-
  شش-   
šeš- (#)

Fr.: hexa-   

A prefix meaning → six. → hexagon.

six.

hexagon
  شش‌بر، شش‌گوش   
šešbar (#), šešguš (#)

Fr.: hexagone   

A six-sided → polygon.

hexa-; → -gon;.

HgMn star
  ستاره‌ی ِ HgMn   
setâre-ye HgMn

Fr.: étoile HgMn   

A → chemically peculiar star of late → B-types. The most distinctive features of HgMn stars are extreme atmospheric overabundance of Hg (up to 5 dex) and of Mn (up to 3 dex). The origin of abundance anomalies observed in late B-type stars with HgMn peculiarity is still poorly understood. More than two thirds of the HgMn stars are known to belong to spectroscopic binaries with a preference of orbital periods ranging from 3 to 20 days (Hurbig et al., 2012, arXiv:1208.2910).

Hg, → mercury; Mn, → manganese; → star. mercury-manganese

Hickson Compact Group (HCG)
  گروه ِ همپک ِ هیکسون   
goruh-e hampak-e Hickson

Fr.: groupe compact de Hickson   

A list of 100 compact groups of galaxies that were identified by a systematic search of the → Palomar Observatory Sky Survey red prints. Each group contains four or more galaxies, has an estimated mean surface brightness brighter than 26.0 magnitude per arcsec2 and satisfies an isolation criterion.

Hickson, Paul, 1982, ApJ 255, 382; → compact; → group.

hidden
  پنهان   
penhân (#)

Fr.: caché   

Being out of sight; concealed.

From M.E., from O.E. hydan, from W.Gmc. *khuthjanan, from PIE *keudh- (cf. Gk. keuthein "to hide, conceal"), from base *(s)keu- "to cover, conceal."

Penhân "hidden," from Mid.Pers. pad nihân, from pad "to, at, for, in" (from O.Pers. paity; Av. paiti "to, toward, in, at;" cf. Skt. práti; Gk. poti) + nihân "concealment, secrecy, hiding place" (Mod.Pers. nahân), from Proto-Iranian *ni-dāna-, from ni- "down; into," → ni- (PIE), + dā- "to put; to establish; to give" (dadâiti "he gives;" cf. Skt. dadâti "he gives;" Gk. didomi "I give;" L. do "I give;" PIE base *do- "to give").

hidden mass
  جرم ِ پنهان   
jerm-e penhân (#)

Fr.: masse cachée   

Same as → missing mass, → non-luminous matter, or → dark matter.

hidden; → mass.

hidden variable
  ورتنده‌ی ِ پنهان   
vartande-ye penhân

Fr.: variable caché   

A theory based on the hypothesis that the discrepancies with respect to classical reality found in → quantum mechanics stem from our lack of knowledge about the observed system (→ EPR paradox). According to this hypothesis, the system should be described by additional quantum parameters, of still unknown nature, but different from position, velocity, spin, etc. The hidden variable theory has been ruled out by the violation of → Bell's inequality for all theories with local property, as suggested by the → Aspect experiment.

hidden; → variable.

hierarchical
  پایگانی   
pâygâni

Fr.: hiérarchique   

Of, belonging to, or characteristic of a hierarchy. → hierarchical clustering; → hierarchical cosmology; → hierarchical multiple system; → hierarchical structure formation.

hierarchy; → -al.

hierarchical clustering
  خوشه‌بندی ِ پایگانی   
xušé bandi-ye pâygâni

Fr.: groupement hiérarchique   

A model in which a system of self-gravitating particles will gradually aggregate into larger and larger gravitationally bound groups and clusters.

hierarchical; → clustering.

hierarchical cosmology
  کیهان‌شناسی ِ پایگانی   
keyhânšenâsi-ye pâygâni

Fr.: cosmologie hiérarchique   

A cosmology characterized by clustering of galaxy clusters in increasingly larger systems.

hierarchical; → cosmology.

hierarchical multiple system
  راژمان ِ بستایی ِ پایگانی   
râžmân-e bastâyi-ye pâygâni

Fr.: système multiple hiérarchique   

A → multiple star system in which the stars can be divided into two groups, each of which traverses a larger orbit around the system's center of mass. Each of these smaller groups must also be hierarchical, which means that they must be divided into smaller subgroups which themselves are hierarchical, and so on. Hierarchical multiple systems have long-term dynamical stability.

hierarchical; → multiple; → system.

hierarchical structure formation
  دیسش ِ ساختار ِ پایگانی   
diseš-e sâxtâr-e pâygâni

Fr.: formation de structures hiérarchiques   

A cosmological → structure formation model in which the smallest gravitationally bound structures (→ quasars and galaxies) form first, followed by → groups, → galaxy clusters, and → superclusters of galaxies.

hierarchical; → structure; → formation.

hierarchical triple system
  راژمان ِ بستایی ِ ناپایگانی   
râžmân-e bastâyi-ye nâpâygâni

Fr.: système multiple non hiérarchique   

A triple star system in which the (inner) binary is orbited by a third body in a much wider orbit. → hierarchical multiple system.

hierarchical; → stellar; → system.

hierarchy
  پایگان   
pâygân (#)

Fr.: hiérarchie   

A system in which the components are organized in increasingly larger structures.

From O.Fr. ierarchie, from M.L. hierarchia "ranked division of angels," from Gk. hierarchia "rule of a high priest," from hierarches "high priest, leader of sacred rites," from ta hiera "the sacred rites" (neut. pl. of hieros "sacred") + archein "to lead, rule."

Pâygân, from pâyé "step, rank, degree," from pây, pâ "foot, step," from Mid.Pers. pâd, pây; Av. pad- "foot" (cf. Skt. pat; Gk. pos, gen. podos; L. pes, gen. pedis; P.Gmc. *fot; E. foot; Ger. Fuss; Fr. pied; PIE *pod-/*ped-) + -gân suffix forming plural entities, from Mid.Pers. -gânag, -gâna, from Proto-Iranian *kāna-ka-.

Higgs boson
  بوسون ِ هیگز   
boson-e Higgs (#)

Fr.: boson de Higgs   

A hypothetical, neutral → elementary particle which plays a key role in the → standard model of → particle physics. This massive particle, whose mass is estimated to be about 125 GeV (→ giga → electron-volts) and a zero → spin, carries the → Higgs field. In the current version of the → electroweak theory, → W boson and → Z boson and all the fundamental constituents (→ quarks and → leptons) get their masses by interacting with the Higgs boson. The Higgs boson is produced by the fusion of two → gluons via a triangular loop of virtual top quarks. In the decay process, a loop of virtual top quarks allows the Higgs boson to decay into two photons. The particle's discovery was announced by → CERN in July 2012.

Named after the Scottish physicist Peter Ware Higgs (1929-), one of the researchers who theorized the existence of this particle in 1964. In fact three groups of physicists almost simultaneously published their results on this subject: François Englert and Robert Brout in August 1964; Peter Higgs in October 1964; and Gerald Guralnik, Carl Hagen, and Tom Kibble in November 1964; → boson.

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