An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 611
ion rays
  پرتوهای ِ یونی   
partowhâ-ye yoni (#)

Fr.: rayons ioniques   

The thin glowing streamers in a comet's ion tail.

ion; → ray.

ion tail
  دنباله‌ی ِ یونی   
donbâle-ye yoni (#)

Fr.: queue d'ions   

Of a comet, same as → gas tail.

gas; → tail.

yoni (#)

Fr.: ionique   

Of or pertaining to ions; occurring in the form of ions.

From → ion + → -ic.

ionic abundance
  فراوانی ِ یونی   
farâvâni-ye yoni

Fr.: abondance ionique   

A quantity, pertaining to an ion of a chemical element, expressing the relative number of the ion with respect to that of hydrogen.

ionic; → abundance.

ionic molecule
  مولکول ِ یونی   
molekul-e yoni

Fr.: molécule ionique   

A molecule that consists of the ions of the chemical elements that make up the molecule.

ionic; → molecule.

yoneš (#)

Fr.: ionisation   

The process by which ions are produced, typically occurring by interaction with electromagnetic radiation ("photoionization"), or by collisions with atoms or electrons ("collisional ionization").

Verbal noun of → ionize.

ionization correction factor (ICF)
  کروند ِ ارشایش ِ یونش   
karvand-e aršâyeš-e yoneš

Fr.: facteur de correction d'ionisation   

A quantity used in studies of → emission nebulae to convert the → ionic abundance of a given chemical element to its total → elemental abundance. The elemental abundance of an element relative to hydrogen is given by the sum of abundances of all its ions. In practice, not all the ionization stages are observed. One must therefore correct for unobserved stages using ICFs. A common way to do this was to rely on → ionization potential considerations. However, → photoionization models show that such simple relations do not necessarily hold. Hence, ICFs based on grids of photoionization models are more reliable. Nevertheless here also care should be taken for several reasons: the atomic physics is not well known yet, the ionization structure of a nebula depends on the spectral energy distribution of the stellar radiation field, which differs from one model to another, and the density structure of real nebulae is more complicated than that of idealized models (see, e.g., Stasińska, 2002, astro-ph/0207500, and references therein).

ionization; → correction; → factor.

ionization energy
  کاروژ ِ یونش   
kâruž-e yoneš

Fr.: énergie d'ionisation   

Same as → ionization potential.

ionization; → energy.

ionization front
  پیشان ِ یونش   
pišân-e yoneš

Fr.: front d'ionisation   

An abrupt discontinuity between an H II region and the molecular cloud in which it has formed. In this transition region interstellar gas changes from a mostly neutral state to a mostly ionized state.

ionization; → front.

ionization parameter
  پارامون ِ یونش   
pârâmun-e yoneš

Fr.: paramètre d'ionisation   

A ratio representing the number of ionizing photons to the number of electrons in a nebular emitting region.

ionization; → parameter.

ionization potential
  توند ِ یونش   
tavande yoneš

Fr.: potentiel d'ionisation   

The energy required to remove an electron from an isolated atom or molecule. The ionization potential for hydrogen is 13.6 eV, which corresponds to an ultraviolet ionizing photon with a wavelength of 912 A. Also called → ionization energy.

ionization; → potential.

ionization stratification
  چینه‌بندی ِ یونش   
cine-bandi-ye yoneš

Fr.: stratification d'ionisation   

The spatial distribution of ionic species around an ionization source according to their → ionization potentials. The higher the ionization potential, the nearer to the source the corresponding ions will be.

ionization; → stratification.

ionization-bounded H II region
  ناحیه‌ی ِ II H‌ی ِ یونش‌کران‌مند   
nâhiye-ye H II-e yoneš-karânmand

Fr.: région H II bornée par ionisation   

An H II region whose → exciting star(s) do not have enough → Lyman continuum photons to ionize the whole region. → density-bounded H II region.

ionization; → bounded; → H II region.

yonidan (#)

Fr.: ioniser   

To change into ions. Verbal form of → ionization.

From → ion + → -ize.

yonidé (#)

Fr.: ionisé   

Converted into ions.

P.p. of → ionize.

ionized gas
  گاز ِ یونیده   
gâz-e yonidé (#)

Fr.: gaz ionisé   

A gas composed partially or totally of → ions.

ionized; → gas.

ionized hydrogen region
  ناحیه‌ی ِ هیدروژن ِ یونیده   
nâhiye-ye hidrožen-e yonidé (#)

Fr.: région d'hydrogène ionisé   

Same as → H II region.

ionized; → hydrogen; → region.

ionized nebula
  میغ ِ یونیده   
miq-e yonidé

Fr.: nébuleuse ionisée   

A cloud of matter in the → interstellar medium consisting of → ionized gas, mainly → hydrogen, and → dust. Same as → H II region.

ionized; → nebula.

ionizing radiation
  تابش ِ یوننده   
tâbeš-e yonandé (#)

Fr.: rayonnement ionisant   

A photon that has enough energy to remove an electron from an atom or molecule, thus producing an ion and free electrons.

Ionizing, adj. from → ionize; → radiation.

yonsepehr (#)

Fr.: ionosphère   

The region of the Earth's upper atmosphere containing a small percentage of free electrons and ions produced by photoionization of the constituents of the atmosphere by solar ultraviolet radiation.

ion + → sphere.

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