An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 420 Search : per
Modules for Experiments in Stellar Astrophysics (MESA)

Fr.: MESA   

An open-source, one-dimensional astrophysical code which is capable of calculating the evolution of stars in a wide range of environments. It works according to the → Henyey method and uses many modules that deal with various aspects of the theoretical models, such as the → equation of state (EOS), → nuclear reaction networks, → chemical composition, micro-physics, or macro-physics. The EOS and corresponding opacities or nuclear networks are provided in tabulated formats and can be selected by the user, while the micro-physics and macro-physics can be controlled by inlists of relevant parameters and settings (Paxton et al. 2015, ApJS 220, 15 and references therein).

module; → experiment; → stellar; → astrophysics.

natural period
  دوره‌ی ِ زاستاری   
dowre-ye zâstâri

Fr.: période naturelle   

Of a body or system, the period of → free oscillation.

natural; → period.

noise temperature
  دمای ِ نوفه   
damâ-ye nufé

Fr.: température de bruit   

A means for specifying the noise generated as unwanted → electromagnetic radiation in a receiver system or one of its components. It is usually measured in terms of the equivalent temperature in a → Rayleigh-Jeans spectrum. Noise temperature is used mainly in radio astronomy.

noise; → temperature.

non-dispersive medium
  مدیم ِ ناپاشنده   
madim-e nâpâšandé

Fr.: milieu non dispersif   

A medium in which the → phase velocity is independent of frequency.

non-; → dispersive; → medium.

normal dispersion
  پاشش ِ هنجارمند   
pâšeš-e hanjârmand

Fr.: dispersion normale   

The dispersion in which a shorter wavelength is associated with a higher → refractive index. Contrasted with the → anomalous dispersion.

normal; → dispersion.

  آپاریدنیگی، آپارش‌پذیری   
âpâridanigi, âpârešpaziri

Fr.: opérabilité   

The capability of being put into use, operation, or practice.

operable; → -ity.

  آپاریدنی، آپارش‌پذیر   
âpâridani, âpârešpazir

Fr.: opérable   

Capable of operating or of being operated.

operate; → -able.


Fr.: opérer   

To function or work; to make something function or work.

From L. operari "to work, labor," L. opus "a work, labor, exertion," Av. *āpah-, *apah- "to do, operate," see below, Skt. ápas- "work, action, religious act;" O.H.G. uoben "to start work, to practice, to honor;" Ger. üben "to exercise, practice;" Du. oefenen; O.E. æfnan "to perform, work, do," afol "power"); PIE base *op- "to work, perform."

Âpâridan, from âpâr-, from Av. *āp(ah)- "to do, operate," as above, + suffix -ar (as in vadar- "weapon," zafar- "jaw," baēvar- "thousand," and so on), shifted to -âr, + -idan suffix of infinitives. The Av. *āpah- "to do, operate," is extant in Mod.Pers. xub "good;" Mid.Pers. hwp, xub "good;" from Av. huuāpah- "doing good work, masterly," from huu-, hv- "good" → eu- + āpah- "work, deed," hauuapanha- "creativity;" cf. Skt. sv-ápas- "doing good work, skillful;" PIE base *op-, as above.

operating system (OS)
  راژمان ِ آپارش   
râžmân-e âpâreš

Fr.: système d'exploitation   

The program that, after being initially loaded into the → computer by a boot program, → manages all the other → programs in a computer.

operating; → system.


Fr.: opération   

1) General: An act or instance, process, or manner of functioning or operating.
2a) Math.: A mathematical process, as addition, multiplication, or differentiation.
2b) The action of applying a mathematical process to a quantity or quantities.
3) Computers: An action resulting from a single instruction.

Verbal noun of → operate


Fr.: opérationnel   

Pertaining to a process or series of actions for achieving a result.

Adj. of → operation.

operational calculus
  افماریکِ آپارشی   
afmârik-e âpâreši

Fr.: calcul opérationnel   

A method of mathematical analysis which in many cases makes it possible to reduce the study of differential operators, pseudo-differential operators and certain types of integral operators, and the solution of equations containing them, to an examination of simpler algebraic problems. It is also known as operational analysis.

operational; → calculus.


Fr.: opérationalisme   

In the philosophy of science, the view that → concepts are defined in terms of measuring operations which determine their applicability. Same as operationism.

operation; → -ism.


Fr.: opérateur   

Math.: Something that acts on another function to produce another function. In linear algebra an "operator" is a linear operator. In calculus an "operator" may be a differential operator, to perform ordinary differentiation, or an integral operator, to perform ordinary integration.

From → operate; + → -or.

orbital period
  دوره‌یِ مداری   
dowre-ye medâri (#)

Fr.: période orbitale   

The time interval between two successive passages of an object through the same point in its orbit around another object.

orbital; → period .

pair-instability supernova
  اَبَر-نووای ِ ناپایداری ِ جفت، اَبَر-نو‌اختر ~ ~   
abar-novâ-ye nâpâydâri-ye joft, abar-now-axtar-e ~ ~

Fr.: supernova à instabilité de paires   

A special type of → supernova that would result from the → pair instability in → supermassive stars with a mass range between 140 and 260 Msun in a low → metallicity environment. Such objects descended from the → Population III stars in the early history of the Universe. Such supernovae are the most powerful thermonuclear explosions in the Universe. Pair-instability supernovae may have played an important role in the synthesis of → heavy elements. Moreover, the energetic feedback of the processed elements to their surroundings could have affected the structure and evolution of the early Universe (See, e.g., Fryer et al. 2001, ApJ 550, 372; Heger & Woosley 2002, ApJ 567, 532). See also → pulsational pair-instability supernova.

pair; → instability; → supernova.

  پان‌دانه‌وری، سراسردانه‌وری   
pân-dâne-vari, sarâsar-dâne-vari

Fr.: panspermie   

The hypothesis that life exists and is distributed throughout the Universe in the form of "seeds" that develop in the right environment. The oldest record of this idea may be traced back to the ancient Greek philospher Anaxagoras, who lived in the fifth century B.C.

N.L., from Gk. panspermia "mixture of all seeds," from → pan- + -sperm, a combining form of sperma "seed" + -ia a noun suffix.

Pân-dâne-vari, sarâsar-dâne-vari, from pân-, sarâsar-, → pan-, + dâné "seed, grain" (Mid.Pers. dân, dânag "seed, corn," Av. dânô- in dânô.karš- "carrying grains; an ant," Skt. dhânâ- "corn, grain," Tokharian B tâno "grain," cf. Lith. duona "corn, bread") + -var suffix of possession, variant -ur (Mid.Pers. -uwar, -war; from O.Pers. -bara, from bar- "to bear, carry") + -i noun suffix.

  ۱) کاغذ؛ ۲) وتار   
1) kâqaz; 2) vetâr (#)

Fr.: papier   

1) A thin sheet made from fibrous material (wood pulp, rags, straw, etc.) suitable for writing or printing on.
2) A written or printed document or the like.

From M.E. papire, from L. papyrus "paper," from Gk. papyros "any plant of the paper plant genus," may be of Egyptian origin.

Kâqaz "paper," probably a transliteration of old Chinese gu zhi; cf. Sogd. kāγaδā "paper," Skt. kakali, kakari, Marathi kagad, Tamil kagidam, Malayalam kayitam (Y. Kumar, 2005, A History of Sino-Indian Relations).

parts per million (ppm)
  پار در میلیون   
pâr dar milion

Fr.: partie par million   

A fraction of a whole number in units of 1/1000,000. It is usually used to describe chemical concentrations, very small amounts of pollutants in air, water, body fluids, and uncertainty. For example 30 ppm is 3 x 10-5 or 0.003%.

part; → per; → million.

Pascal's barrel experiment
  آزمایش ِ چلیک ِ پاسکال   
âzmâyeš-e celik-e Pascal

Fr.: expérience du tonneau de Pascal   

An experiment carried out by Blaise Pascal in 1646 to demonstrate the hydraulic pressure. A long and narrow vertical pipe was connected to the content of a closed wooden barrel already full of water. He poured a small quantity of water into the pipe, whereby the height of the fluid within the pipe sharply increased. Due to the increase in hydrostatic pressure and → Pascal's law, the barrel could leak and even burst.

pascal (Pa); M.E. barel, from M.Fr. baril, O.Fr. barril; → experiment

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