An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 9 Search : quasi-
quasi-
  چونان-، -وش   
cunân-, -vaš

Fr.: quasi-   

A prefix meaning "resembling, almost, having some, but not all of the features of."

From L. quasi "as if, as though," from qua(m)" as" + si "if."

Cunân "so, like that; just as if," from cun "how?," (Mid.Pers. cigôn "how?," cigônêh "nature, character," O.Pers/Av. ci- "what, any," collateral stem to ka- "who?, what?;" cf. Skt. ka-; Gk. po-; L. quo-; E. what, who; PIE *qwos/*qwes) + suffix ân. -vaš a suffix of similitude.

quasi-atom
  چونان-اتم، اتم‌وَش   
cunân-atom, atom-vaš

Fr.: quasi-atome   

A system in which the nuclei of two colliding atoms approach each other closely for a brief lapse of time so that their electrons are arranged in atomic orbitals characteristic of a single atom with combined atomic number.

quasi-; → atom.

quasi-closed subsystem
  زیر-راژمان ِ چونان‌بسته   
zir-râžmân-e cunân-basté

Fr.: sous-système quasi-fermé   

A subsystem if its intrinsic energy is large, on the average, with respect to the energy of its interaction with other portions of the → closed system.

quasi-; → closed; → subsystem.

quasi-linear theory
  نگره‌ی ِ چونان-خطی   
negare-ye cunân-xatti

Fr.: théorie quasi-linéaire   

In plasma physics, the theory that considers the interactions between waves and particles are of first order only. It ignores all terms of second order in the fluctuating quantities.

quasi-; → linear; → theory.

quasi-satellite
  چونان‌ماهواره، چونان‌بنده‌وار   
cunân-mâhvâré, cunân-bandevâr

Fr.: quasi-satellite   

An asteroid moving around the Sun having the same mean motion and mean → longitude as a planet, but a different → eccentricity. The asteroid remains near the planet much like a satellite even when its distance is large enough so that it is well outside the planet's → Hill sphere. The quasi-satellite motion is one class of possible → co-orbital motions of small bodies in 1:1 mean-motion → resonance with a planet. If the quasi-satellite orbit is coplanar with the planet, then the motion is stable in the → secular approximation. When the orbits are inclined enough, an asteroid can be trapped into such a motion for a finite period of time. Earth has several quasi-satellites (mainly 3753 Cruithne, 2002 AA29, 2003 YN107), also does Venus (the only one so far discovered, 2002 VE68). The possibility of such orbits was first suggested by J. Jackson (1913, MNRAS 74, 62).

The term quasi-satellite was first used by S. Mikkola & K. Innanen 1997, The Dynamical Behaviour of our Planetary System; Proceedings, p. 345); → quasi-; → satellite.

quasi-separatrix layer (QSL)
  لایه‌ی ِ چونان‌جداگر   
lâye-ye cunân-jodâgar

Fr.: couche quasi-séparatrice   

A region of the solar atmosphere where the gradient of the field line → linkage from one boundary to another is large so that the field lines can slip-run rapidly through the → plasma. The QSL results from → magnetic reconnection without → null point.

quasi-; → separatrix; → layer.

quasi-single-scattering approximation
  نزدینش ِ چونان-تک‌پراکنش   
nazdineš-e cunân-tak-parâkaneš

Fr.:   

A model of radiative transfer that ignores forward scattering of photons; assuming forward-scattered light as un-scattered.

quasi-; → single; → scattering; → approximation.

quasi-stellar object
  بر‌آخت ِ چونان‌ستاره‌ای   
barâxt-e cunân-setâre-yi

Fr.: objet quasi-stellaire   

Initial name of → quasars.

quasi-; → stellar; → object.

quasi-stellar radio source
  ر‌آدیو-خن ِ چونان‌ستاره، ~ ~ ِ ستاره‌وش   
râdio-xan-e cunân setâré, ~ ~ setâré-vaš

Fr.: radiosource quasi-stellaire   

A quasar with detectable radio emission.

quasi-; → stellar; → radio; → source.