An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1965 Search : ion
broad-line region (BLR)
  ناحیه‌ی ِ پهن-خط   
nâhiye-ye pahn-xatt

Fr.: région à raies larges   

The inner region of a → quasar or an → active galactic nucleus exhibiting broad → spectral lines which indicate ionized matter moving with speeds in excess of 10,000 km sec-1, probably due to the presence of an → accretion disk surrounding a → supermassive black hole. Also called Type I AGN. See also → obscuring torus.

broad; → line; → region.

Brownian motion
  جنبش ِ براؤنی   
jonbeš-e Brawni

Fr.: mouvement brownien   

The continuous random motion of solid microscopic particles immersed in a fluid, which is due to bombardment by the atoms and molecules of the medium. It is named after the botanist Robert Brown, who in 1827 first noticed that pollen seeds suspended in water moved in an irregular motion. While there were suspicions that the motion was caused by the collision of atoms against the particles, the first quantitative explanation of the phenomenon, based on the kinetic theory of gases, was forwarded by A. Einstein in 1905. When Einstein's paper appeared, the notion of atoms and molecules was still a subject of heated scientific debate. Ernst Mach and the physical chemist Wilhelm Ostwald were among those who chose to deny their existence.

Named after Robert Brown (1773-1858), a Scottish botanist, who first in 1827 noticed the erratic motion of pollen grains suspended in water. → motion.

burst of star formation
  بلک ِ دیسش ِ ستارگان   
belk-e diseš-e setâregân

Fr.: flambée de formation d'étoiles   

An intense → star formation activity in a region of → interstellar medium or, more globally, in a → galaxy. It is characterized by a → star formation rate which is much higher than the corresponding average. Same as → starburst.

burst; → star; → formation.

c Orionis
   c-شکارگر، c-اریون   
c-Šekârgar, c-Oyon

Fr.: c Orionis   

Same as → 42 Orionis.

Star name in the → Bayer designation scheme.


Fr.: calcul   

The act, process, or result of calculating.

Calculation, noun from → calculate.

Afmâreš, verbal noun from afmârdancalculate.

calculus of variations
  افماریک ِ ورتش‌ها   
afmârik-e vartešhâ

Fr.: calcul des variations   

The study of maximum and minimum properties of → definite integrals.

calculus; → variation.

Afmârik, → calculus; vartešvariation.


Fr.: étalonnage, calibration   

1) The act or process of calibrating or the state of being calibrated.
2) A set of graduations that show positions or values.

Calibration, noun from → calibrate.

Kabizeš, noun from kabizidan, → calibrate.

calibration curve
  خمِ کبیزش   
xam-e kabizeš

Fr.: courbe d'étalonnage   

An empirical curve obtained through appropriate exposures in order to determine the instrument's response. For example, a curve allowing the conversion of relative intensities of an observed object into absolute fluxes, or a curve relating the detector's pixel positions to wavelengths.

calibration; → curve.

calibration error
  ایرنگِ کبیزش   
irang-e kabizeš

Fr.: erreur d'étalonnage   

A systematic error in the constant values to be applied to a measuring instrument.

calibration; → error.

Irang, → error; kabizeš, → calibration.

calibration exposure
  نوردادِ کبیزش   
nurdâd-e kabizeš

Fr.: pose d'étalonnage   

An exposure obtained with an instrument mounted on the telescope using an artificial illuminating source in order to calibrate the instrument.

calibration; → exposure.

Nurdâd, → exposure; kabizeš, → calibration.

calibration lamp
  لامپِ کبیزش   
lâmp-e kabizeš

Fr.: lampe d'étalonnage   

A lamp used for instrument calibration, such as an internal He-Ar arc for wavelength calibration or an external source of light placed in the telescope dome for flat-field exposures.

calibration; lamp, from O.Fr. lampe, L. lampas, from Gk. lampas "torch, lamp, light, meteor," from lampein "to shine."

Kabizeš, → calibration; lâmp, from Fr., as above.

canonical correlation
  هم‌باز‌آنشِ هنجاروار   
hambâzânš-e hanjârvâr

Fr.: correlation canonique   

The highest correlation between linear functions of two data sets when specific restrictions are imposed upon them.

canonical; → correlation.

canonical equation
  هموگشِ هنجاروار   
hamugeš-e hanjârvâr

Fr.: équation canonique   

The most general form of an equation.

canonical; → equation.

capillary action
  ژیرش ِ مویینه، مویینگی   
žireš-e muyiné, muyinegi

Fr.: capillarité   

The ability of a → liquid to → flow in a → narrow space, such as a thin → tube, without the assistance of, and in opposition to, external forces like → gravity. Also called → capillarity. It occurs because of intermolecular → attractive forces between the liquid and solid surrounding surfaces. If the diameter of the tube is sufficiently small, then the combination of → surface tension (which is caused by → cohesion within the liquid) and → adhesion (between the liquid and the → container) acts to lift the liquid. The capillarity of the liquid is high when adhesion is greater than cohesion. For example, water in a thin glass tube has strong → adhesive forces due to the hydrogen bonds that form between the water molecules and the oxygen atoms in the glass wall (made of → silica, SiO2). In contrast, mercury is characterized by stronger cohesion, and hence its capillarity is much lower.

capillary; → action.


Fr.: légende   

1) A title or explanation for a picture or illustration, especially in a magazine.
2) A heading or title, as of a chapter, article, or page (

M.E. capcio(u)n "taking, seizure," from capcion "arrest, capture, imprisonment," or directly from L. caption-, from capt(us) "taken," → capture.

Kapéš "taking, capture," verbal noun from kapidan "to seize, take, capture," related to qâpidan, qâp zadan "to rob, to seize," Malâyeri qapâl "robbing, seizure, robbing," probably related to L. capere, → capture.

cardinal direction
  سوی ِ اگرا   
su-ye agrâ

Fr.: point cardinal   

Any of the four principal directions or points of the compass, → north, → east, → south, and → west. See also: → cardinal point.

cardinal; → direction.

Carrington rotation
  چرخش ِ کرینگتون   
carxeš-e Carrington

Fr.: rotation de Carrington   

A system for counting rotations of the Sun based on the mean → synodic rotation period of the Sun. Initially, Lord Carrington determined the solar rotation rate by watching low-latitude → sunspots. He defined a fixed solar coordinate system that rotates in a sidereal frame exactly once every 25.38 days. This means that the solar rotation period, as viewed from the Earth, is assumed to be constant. However, the synodic rotation rate varies during the year because of the changing speed of the Earth in its orbit and the mean synodic period is about 27.2753 days. Carrington rotation number 1 began on November 9, 1853.

Named for Richard C. Harrington (1826-1875), British astronomer, who initiated the system; → rotation.

cascade transition
  گذرش ِ پی‌شاری   
gozareš-e peyšâri

Fr.: transition en cascade   

A photon generation mechanism in an atom in which a transition initiates a series of secondary transitions from lower electronic levels.

cascade; → transition.

Cassini division
  شکاف ِ کاسینی   
šekâf-e Cassini (#)

Fr.: division de Cassini   

The main dark gap, 4,700 km wide, which divides Saturn's outermost A and B rings.

Named after Jean-Dominique Cassini (1625-1712), French astronomer of Italian origin, who discovered the division in 1675; → division.

catalog position
  نهش ِ کاتالوگی   
neheš-e kâtâlogi

Fr.: position catalogue   

Same as catalog place and → mean catalog place.

catalog; → position.

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