An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 645
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.

Iota Orionis
  یوتا-شکارگر، یوتا-اریون،   
Iota-Šekârgar, Iota-Oryon

Fr.: Iota Orionis   

A → multiple star system in the → Orion constellation. Also known as → Hatsya, → Na'ir al-Saif, and HR 1899. It is the brightest star of → Orion's Sword, located at the sword's tip, with an → apparent visual magnitude of 2.8. From parallax measurements, it is located at a distance of roughly 1,330 → light-years (410 parsecs) from the Sun. The system has three components designated Iota Orionis A, B and C. Iota Orionis A is itself a massive spectroscopic binary, with components Iota Orionis Aa and Ab.

Iota, Greek letter ι used in the → Bayer designation of star names; Orionis, genitive of → Orion.


Fr.: IRAF   

A general purpose software package for the reduction and analysis of astronomical data. It is aimed specifically at the reduction of imaging and spectroscopy data obtained using → CCD detector systems. IRAF is developed by the National Optical Astronomy Observatories (NOAO).

Short for Image Reduction and Analysis Facility.

Iranian calendar
  گاهشمار ِ ایرانی   
gâhšomâr-e Irâni (#)

Fr.: calendrier iranien   

The most accurate solar calendar in use, which is based on two successive passages of the Sun through the true vernal equinox. The year length, defined by an ingenious intercalation system devised by the mathematician Omar Khayyâm (A.D. 1048-1131), is 365.2424.. solar days, in perfect agreement with the → vernal-equinox year of 365.24236 solar days (epoch +2000). This interval should not be confounded with the → tropical year of 365.2422 solar days. The most remarkable feature of the calendar is Nowruz, the spring festival, which has its profound roots in the Zoroastrian worldview. Same as → Persian calendar. Click here for more details.

Iranian, of or pertaining to Iran "(land of) the Aryans," as below; → calendar.

Gâhšomâr, → calendar; Irâni adj. of Irân, from Mid.Pers. Êrân "(land of) the Aryans," pluriel of êr "noble, hero," êrîh "nobility, good conduct;" Parthian Mid.Pers. aryân; O.Pers. ariya- "Aryan;" Av. airya- "Aryan;" cf. Skt. ārya- "noble, honorable, respectable."


Fr.: iridescence   

The condition or state of being → iridescent; exhibition of colors like those of the → rainbow.

From L. iris (genitive iridis) "rainbow," + → -escence.


Fr.: iridescent   

Producing a display of lustrous, rainbow-like colors.


iridiom (#)

Fr.: iridium   

A metallic chemical element; symbol Ir. Atomic number 77; atomic weight 192.22; melting point about 2,410°C; boiling point about 4,130°C; specific gravity 22.55 at 20°C. Iridium is a very hard, usually brittle, extremely corrosion-resistant silver-white metal with a face-centered cubic crystalline structure. The unusually high concentration of iridium found in the thin clay layer that marks the boundary between the Cretaceous and Tertiary rocks is attributed to an asteroid impact with Earth 65 million years ago.

Iridium coined 1804 by its discoverer, E. chemist Smithson Tennant (1761-1815) from Gk. → iris "rainbow;" so called for the varying color of its compounds.

  ۱) تیتک؛ ۲) ایریس؛ ۳) زنبق   
1) titak; 2) Iris; 3) zanbaq

Fr.: iris   

1a) The circular diaphragm forming the colored portion of the eye and perforated by the pupil in its center. → pupil.
1b) A diaphragm forming an adjustable opening over a lens in an optical instrument.
2) Asteroid 7, discovered in 1847 by E. astronomer John Russell Hind (1823-1895).
3) Botany: A plant having showy flowers, typically of purple, yellow, or white, and long thin leaves.

Iris, M.E., from L. irid-, iris "colored part of the eye, rainbow, iris plant, a precious stone," from Gk. iris, iridos "rainbow, iris plant, iris of the eye," initially "a messenger of the gods, regarded as the goddess of the rainbow." The eye portion was so called for being the colored part.

Titak, from Kermâni, Tâleši, variants Lori tiya, Dehxodâ dictionary tuk, probably from didan "to see," Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Av. dā(y)- "to see," didāti "sees;" cf. Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen."
Zanbaq, from Pers. zanba "white rose."

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