An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 30 Search : electron
Auger electron
  الکترون ِ اژه   
elektron-e Auger

Fr.: électron d'Auger   

An electron that is emitted when an electron from a higher → energy level falls into a → vacancy in an inner shell, according to the → Auger-Meitner effect. The process usually occurs when the atom is bombarded with high energy electrons. If the collision ejects an inner-shell electron, an electron from a higher level will quickly drop to this lower level to fill the vacancy. Most of the time, the energy is released in the form of a photon. But sometimes the energy is transferred to another electron, which is ejected from the atom.

Auger-Meitner effect; → electron.

conduction electron
  الکترون ِ هازش   
elektron-e hâzeš

Fr.: électron de conduction   

An electron whose energy lies in the conduction band of a solid, where it is free to move under the influence of an electron field.

conduction; → electron.

elektron (#)

Fr.: électron   

The → elementary particle that possesses the smallest possible negative → electric charge. This structureless particle has an intrinsic → spin (1/2), a mass of 9.109 382 91 (40) x 10-31 kg, and an electric charge of 1.602 176 565(35) × 10-19 → coulombs, or 4.803 204 51(10) × 10-10 → esu.

Term first suggested in 1891 by Irish physicist G. J. Stoney (1826-1911); from electr-, from → electric + -on, a suffix used in the names of subatomic particles, probably extracted from → ion.

electron affinity
  کرونی ِ الکترونی   
karvani-ye elektroni

Fr.: affinité électronique   

The amount of energy released or absorbed in the process in which an electron is added to a neutral atom or molecule in gaseous state to form a negative ion.

electron; → affinity.

electron capture
  گیر‌افت ِ الکترون   
giroft-e elektron

Fr.: capture d'électron   

A process whereby an → unstable atom becomes stable. In this process, an → electron in an atom's inner shell is drawn into the → nucleus where it combines with a → proton, forming a → neutron and a → neutrino. The neutrino escapes from the atom's nucleus. The result is an element change, because the atom loses a proton. For example, an atom of → carbon (with 6 protons) becomes an atom of → boron (with 5 protons). Electron capture is also called K-capture since the captured electron usually comes from the atom's K-shell. See also → neutronization.

electron; → capture.

electron charge
  بار ِ الکترون   
bâr-e elektron (#)

Fr.: charge de l'électron   

The charge of one electron, e = -1.602 176 × 10-19coulombs or -4.803 204 51 × 10-10statcoulombs.

electron; → charge.

electron configuration
  همپیکرش ِ الکترونی   
hampeykareš-e elektroni

Fr.: configuration électronique   

Of an atom, a form of notation which shows how the electrons are distributed among the various atomic orbital and energy levels. The format consists of a series of numbers, letters and superscripts. For example, 1s2 2s2 2p3 means: 2 electrons in the 1s subshell, 2 electrons in the 2s subshell, and 3 electrons in the 2p subshell.

electron; → configuration.

electron degeneracy
  واگنی ِ الکترون   
vâgeni-ye elektron (#)

Fr.: dégénérescence des électrons   

A → degenerate matter in which electrons are very tightly packed together, as in a white dwarf, but cannot get closer than a certain limit to each other, because according to quantum mechanics laws (→ Pauli exclusion principle) the lowest energy levels can be occupied by only one electron. Therefore, electrons are forced into high energy states. And the significant pressure created by these high energy electrons supports white dwarf stars against their own gravity.

electron; → degeneracy.

electron density
  چگالی ِ الکترونی   
cagâli-ye elektroni (#)

Fr.: densité électronique   

The number of electrons per unit volume in an ionized medium, like an → H II region, as determined from → emission lines.

electron; → density.

electron diffraction
  پراش ِ الکترونی   
parâš-e elekroni (#)

Fr.: diffraction des électrons   

A diffraction phenomenon resulting from the passage of electrons through matter, analogous to the diffraction of visible light. This phenomenon is the main evidence for the existence of waves associated with elementary particles; → de Broglie wavelength.

electron; → diffraction.

electron mass
  جرم ِ الکترون   
jerm-e elekron (#)

Fr.: masse de l'électron   

The mass of an electron, which is 9.109 382 91 × 10-28 g.

electron; → mass.

electron radius
  شعاع ِ الکترون   
šo'â'-e elektron

Fr.: rayon de l'électron   

The classical size of the electron given by re = e2/mec2 = 2.81794 × 10-13 cm, where e and me are the → electron charge and → electron mass, respectively, and c is the → speed of light.

electron; → radius.

electron shell
  پوسته‌ی ِ الکترونی   
puste-ye elekroni (#)

Fr.: couche éléctronique   

Any of up to seven energy levels on which an electron may exist within an atom, the energies of the electrons on the same level being equal and on different levels being unequal. The number of electrons permitted in a shell is equal to 2n2. A shell contains n2 orbitals, and n subshells.

electron; → shell.

electron temperature
  دمای ِ الکترونی   
damâ-ye elektroni (#)

Fr.: température électronique   

1) The temperature of electrons in an interstellar ionized nebula (e.g. in → H II regions and → planetary nebulae) as determined by characteristic → emission lines (optical → forbidden lines or → radio recombination lines).
2) In the → solar wind, the temperature derived from the mean → thermal agitation of the electrons. More specifically, electric field receivers on board space probes carry out the spectroscopy of the → thermal noise due to the potential fluctuations produced by the thermal agitation of the electrons, yielding the electron temperature in certain conditions (N. Meyer-Vernet, 2007, Basics of the Solar Wind, Cambridge Univ. Press). See also → proton temperature.

electron; → temperature.

electron volt (eV)
elektron-volt (#)

Fr.: électron-volt   


electron; → volt.

electron-positron pair
  جفت ِ الکترون-پوزیترون   
joft-e elektron-pozitron (#)

Fr.: paire électron-positron   

The simultaneous formation of an → electron and a → positron in the → pair production process.

electron; → positron; → pair.

electron-scattering wing
  بال ِ پراکنش ِ الکترون   
bâl-e parâkaneš-e elektron


A → line broadening phenomenon involving the scattering effect of → free electrons on the → radiation transfer in → stellar atmospheres. The scattering of radiation by free electrons plays an important role in the atmospheres of → hot stars, such as → O-types, early → B-types, and → Wolf-Rayet stars. The first detailed study of electron scattering in Wolf-Rayet stars was by Castor et al. (1970), who used electron scattering to explain the broad emission wings of N IV λ3483 in HD 192163. In → P Cygni stars the explanation of the very extended (almost symmetric) wings on the → Balmer lines as caused by electron scattering was first made by Bernat & Lambert (1978). Hillier (1991) showed that significant reduction in the strength of an electron-scattering wing can be achieved in a model of → clumped wind for a lower mean → mass loss rate. This resulted in a better agreement between observations and theoretical predictions. Electron-scattering wings provide diagnostics regarding the presence of density inhomogeneities in → stellar winds (Münch, 1948, ApJ 108, 116; Hillier, 1991, A&A 247, 455).

electron; → scattering; → wing.

electron-volt (eV)
elektron-volt (#)

Fr.: électron-volt   

The energy acquired by an electron when accelerated through a → potential difference of 1 volt (1 eV = 1.602 × 10-12 → ergs = 11605 → kelvins).

electron; → volt.

  ۱) الکترونی؛ ۲) الکترونیک   
1) elektroni (#); 2) elektronik (#)

Fr.: électronique   

1) Of or relating to electrons or to an electron.
2) Of or relating to → electronics or to → devices, → circuits, or systems developed through electronics (

electron; → -ic.

electronic state
  استات ِ الکترونی   
estât-e elektroni

Fr.: état éléctronique   

In molecular quantum mechanics, any of → quantum states corresponding to a particular → electron configuration (i.e. an arrangement of the electron(s) in certain → orbitals). The electron configuration with the lowest energy is called the → ground state. All higher energy states are called → excited states.

electronic; → state.

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