An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 474 Search : pH
  شید-بخارش، نور-بخارش   
šidboxâreš, nurboxâreš

Fr.: photoévaporation   

A process going on in a molecular cloud surface whereby the surface material ionized by ultraviolet photons of neighboring stars is dissipated.

photo- + → evaporation.


Fr.: photoexcitation   

The mechanism of raising an electron to higher energies by photon absorption, when the energy of the photon is too low to cause photoionization.

photo- + → excitation.

  عکس، شید-نگار، نور-نگار   
aks, šidnegâr, nurnegâr

Fr.: photographie   

A picture produced by photography. → picture.

From → photo- + → -graph.

Aks, from Ar. 'aks "to inverse, reverse." Šidnegâr, nurnegâr, from šid, nur, → photo-, + negâr, → graph.

photographic magnitude
  بُرز ِ عکسبرداریک   
borz-e aksbardârik

Fr.: magnitude photographique   

The apparent magnitude of a star as determined by measuring its brightness on a photographic plate. The photographic magnitude scale is now considered obsolete.

Adj. of → photography; → magnitude.

photographic survey
  بردید ِ عکسبرداریک   
bardid-e aksbardârik

Fr.: relevé photographique   

Recording a large area of the night sky by photographic techniques, as practiced in the past before the advent of electronic detectors.

Adj. of → photography; → survey.

  عکسبرداری، شید-نگاری، نور-نگاری   
aksbardâri, šidnegâri, nurnegâri

Fr.: photographie   

The process of recording and producing images by exposing light-sensitive detectors to light or other forms of radiation.

photo-, → -graphy.

Aksbardâri, literally "taking photograph," from aks, → photograph, + bardâri verbal noun of bardâštan "to take," composite verb from bar- "on; up; upon; in; into; at; forth; with; near; before; according to" (Mid.Pers. abar; O.Pers. upariy "above; over, upon, according to;" Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-; O.H.G. ubir "over;" PIE base *uper "over") + dâštan "to have, to possess" (Mid.Pers. dâštan; O.Pers./Av. root dar- "to hold, keep back, maintain, keep in mind;" cf. Skt. dhr-, dharma- "law;" Gk. thronos "elevated seat, throne;" L. firmus "firm, stable;" Lith. daryti "to make;" PIE *dher- "to hold, support").
Šidnegâri, nurnegâri, action noun from šidnegâr, nurnegâr, → photograph.

  شید-یونش، نور-یونش   
šid-yoneš, nur-yoneš

Fr.: photoionisation   

The physical process in which an incident high-energy photon ejects one or more electrons from an atom, ion, or molecule.

photo- + → ionization.

  شید-یونیدن، نور-یونیدن   
šid-yonidan, nur-yonidan

Fr.: photoioniser   

To cause, or to undergo → photoionization.

photo-; → ionize.

  شید-یونیده، نور-یونیده   
šid-yonidé, nur-yonidé

Fr.: photoionisé   

Subject to, or produced by → photoionization.

photo-; → ionized.


Fr.: photoluminescence   

A process in which → absorption of photons at → ultraviolet (UV) / → optical wavelengths is followed by → electronic transitions associated with the emission of longer wavelength optical and → near-IR photons. Photoluminescence has two types: → phosphorescence and → luminescence. The excitation of the photoluminescence process under astrophysical conditions results from the absorption of a single UV/optical photon, leading to an electronic transition from a → ground state (1) to a higher state (2). State (2) typically is a bound, high-lying vibrational-rotational level of the first or second electronically excited state of a molecule or molecular ion, or a high state in the → conduction band of a semiconductor particle. The excited system relaxes through a series of → vibrational-rotational transitions until the electron finds itself in an intermediate state (3), from where an optical electronic transition back to the ground state (1) is possible. In a → polycyclic aromatic hydrocarbon (PAH) molecule, for example, state (3) can either be the lowest state in the → singlet or → triplet vibrational-rotational manifold of the first excited electronic level (Witt, A. N., Vijh, U. P., 2003, astro-ph/0309674).

photo-; → luminescence.

  شید-سنج، نور-سنج   
šidsanj, nursanj

Fr.: photomètre   

An instrument for measuring the amount of light.

photo- + → -metry.

  شید-سنجی، شید-سنجیک، نور-سنجی، نور-سنجیک   
šidsanji, šidsanjik, nursanji, nursanjik

Fr.: photométrique   

Pertaining to or related to → photometry.

photometer + → -ic.

photometric band
  باند ِ شیدسنجیک، ~ نورسنجیک   
bând-e šid-sanjik, ~ nur-sanjik

Fr.: bande photométrique   

The range of → wavelengths allowed by a → filter used in a → photometric system.

photometric + → band.

photometric binary
  دُرین ِ شید-سنجیک، ~ نور-سنجیک   
dorin-e šidsanjik, ~ nursanjik

Fr.: binaire photométrique   

A binary star whose binarity is detectable from its variability and light-curve that has certain specific characteristics.

photometric + → binary.

photometric calibration
  کبیزش ِ شید-سنجیک، ~ سنور-سنجیک   
kabizeš-e šidsanjik, ~ nursanjik

Fr.: calibration photométrique   

A calibration which converts the measured relative magnitudes into an absolute photometry.

photometric + → calibration.

photometric parallax
  دیدگشت ِ شیدسنجیک   
didgašt-e šidsanjik

Fr.: parallaxe photométrique   

A method of deriving the distance of a star using its → apparent magnitude and the → absolute magnitude inferred from its → spectral type.

This is a misnomer, because the method has nothing to do with parallax; → photometric; → parallax.

photometric system
  راژمان ِ شید-سنجیک، ~ نور-سنجیک   
râžmân-e šidsanjik, ~ nursanjik

Fr.: système photométrique   

A system of → magnitudes, each of them characterized by a set of well-defined → passbands (or → filters) with known → response curves. The system is defined by the values given for the → standard stars. See also:
AB magnitude system, → five-color system, → Stromgren system, → JHK system, → UBV system, → uvby system.

photometric; → system.

  شید-سنجی، نور-سنجی   
šidsanji, nursanji

Fr.: photométrie   

In astronomy, the measurement of the light of astronomical objects, generally in the visible or infrared bands, in which a wavelength band is normally specified.

photo- + → -metry.

  شید-بستاگر، نور-بستاگر   
šid-bastâgar, nur-bastâgar

Fr.: photomultiplicateur   

Electronic tube which converts photons into electrons, multiplies the electrons via a series of electrodes, and produces a measurable current from a very small input signal.

photo- + → multiplier.

foton (#)

Fr.: photon   

The → quantum of the → electromagnetic field, which mediates the interaction between charged particles. It is the mass-less → boson with zero → electric charge, which propagates with the → speed of light in vacuum. The energy of a photon is connected to its → frequency ν, through the formula E = hν, where h is → Planck's constant.

From phot-, variant of → photo- before a vowel + → -on a suffix used in the names of subatomic particles (gluon; meson; neutron), quanta (photon, graviton), and other minimal entities or components. The term photon was coined by Gilbert N. Lewis in 1926 in a letter to the editor of Nature magazine (Vol. 118, Part 2, December 18, page 874).

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