An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 108 Search : ring
  لاوک زایی، کندال زایی   
lâvakzâyi, kandâlzâyi

Fr.: cratérisation   

The process by which craters form on the surface of Solar System objects.

From → crater + → -ing

From lâvak or kandâl, → crater, + zâyi from zâ- present tense stem of zâdan "to give birth," Mid.Pers. zâtan, Av. zan- "to bear, give birth to a child, be born," infinitive zazâite, zâta- "born," cf. Skt. janati "begets, bears," L. gignere "to beget," PIE base *gen- "to give birth, beget."

crepe ring
  حلقه‌ی ِ پرنیان   
halqe-ye parniyân

Fr.: anneau de crèpe   

An alternative name for Saturn's C ring, which is a wide but faint ring located inside the B Ring. Discovered in 1850 by William and George Bond, it was termed "crepe" because it seemed to be composed of darker material than the brighter A and B Rings.

Crepe, from Fr. crêpe, from O.Fr. crespe, from L. crispa, fem. of crispus "curled;" → ring.

Halqé, → ring; parniyân "a kind of fine painted silk, a mantle of such silk."

D ring
  حلقه‌ی ِ D   
halqe-ye D

Fr.: anneau D   

The inner → Saturn's rings, with a width of 7,500 km, lying before the → C ring, at 66,900 km from the center of Saturn.



Fr.: audacieux   

Taking or willing to take risks; audaciousness.

dare; → -ing.

dark fringe
  فریز ِ تاریک   
fariz-e târik (#)

Fr.: frange noire   

One of the successive dark and light bands produced by diffraction or interference of light.

From O.Fr. frange, from V.L. *frimbia alteration by metathesis of L. fimbria "fringe, edge of garment."

Fariz, variants farviz, farâviz "fringe, edge of garment."

  تیگش، تیگی   
tigeš, tigi

Fr.: affinage   

The process or state of making an image sharper. → deblur; same as sharpening. → deconvolution.

Verbal noun of → deblur.

diamond ring effect
  اسکر ِ انگشتر ِ الماس   
oskar-e angoštar-e almâs

Fr.: effet anneau de diamant   

An intense flash of light that happens a few seconds before and after totality during a solar eclipse. The effect is caused by the last rays of sunlight before totality (or the first rays of sunlight after totality) shining through valleys on the edge of the Moon.

diamond; → ring; → effect.

Oskar, → effect; angoštar "a ring worn on the finger," from angošt "finger," Mid.Pers. angušt "finger, toe," Av. angušta- "toe," from ank- "curved, crooked," cf. Skt. angustha- "thumb," ankah "hook, bent," Gk. angkon "elbow," angkura "anchor," L. angulum "corner" (E. angle), Lith. anka "loop," O.E. ancleo "ankle," O.H.G. ango "hook," PIE base *ang-/*ank- "to bend"; → diamond.

double Compton scattering
  پراکنش ِ کامپتون ِ دوتایی   
parâkaneš-e Compton-e dotâyi

Fr.: diffusion Compton double   

An electron-photon interaction that can be thought of as a → Compton scattering event associated with the production or destruction of an extra photon.

double; → Compton; → scattering.


Fr.: durant   

In the course of, in the time of, throughout the continuance of.

M.E. Duryng, durand, pr.p. of duren "to last, endure, continue, be or exist," from O.Fr. durer, from L. durare "to harden," from durus "hard;" PIE root *deru- "be firm, solid, steadfast."

Tarpây, literally "lasting over time," from tar- "through, across, over time," variant tarâ-, → trans-, + pây present stem and agent noun of pâyidan, → last (v.).

dust scattering
  پراکنش ِ غباری، ~ پت غبار   
parâkaneš-e qobâri, ~ pat qobâr

Fr.: diffusion par la poussière   

The scattering of → photons by → dust grains.

dust; → scattering.

E ring
  حلقه‌ی ِ E   
halqe-ye E

Fr.: anneau E   

The → Saturn's ring, with a width of 300,000 km, lying beyond the → G ring, at 180,000-480,000 km from the center of Saturn.


Einstein ring
  حلقه‌ی ِ اینشتین   
halqe-ye Einstein

Fr.: anneau d'Einstein   

The apparent shape of a background source unsergoing the effect of → gravitational lensing as seen from Earth, provided that the source, the intervening lens, and the observer are in perfect alignement through → Einstein radius.

Einstein; → ring.

elastic scattering
  پراکنش ِ کشایند   
parâkaneš-e kešâyand

Fr.: diffusion élastique   

In a → collision between two → particles, the reaction in which the total → kinetic energy of the system, projectile plus target, is the same before the collision as after.
In the interaction of → electromagnetic waves with particles, the scattering when the → wavelength (→ frequency) of the → scattered light is the same as the → incident light (→ Rayleigh scattering, → Mie scattering).

elastic; → scattering.

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.

mohandesi (#)

Fr.: ingénierie   

The action, work, or profession of an engineer.

engineer + → -ing.

F ring
  حلقه‌ی ِ F   
halqe-ye F

Fr.: anneau F   

The → Saturn's ring, with a width of 30-500 km, lying just outside of the → A ring, at 140,210 km from the center of Saturn.




The final stage of mirror making, a process of altering the mirror's shape into the one required for proper function. → grinding; → polishing.

Figuring, noun of → figure.

Šekldahi, "giving form," from šekl, → figure + dahi, a verbal noun of dâdan "to give," from Mid.Pers. dâdan "to give," O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives;" cf. Skt. dadáti "he gives," Gk. didomi "I give," tithenai "to put, set, place;" L. dare "to give, offer;" facere "to do, to make;" Rus. delat "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do." PIE base *dhe- "to put, to do."

fingering convection
  همبز ِ انگشتوار   
hambaz-e angoštvâr


A weak yet important kind of mixing that results from → fingering instability in stars within → radiative zones that have an unstable mean → molecular weight  → gradient. Also called → thermohaline convection.

finger; → -ing; → convection.

fingering instability
  ناپایداری ِ انگشتوار   
nâpâydâri-ye angoštvâr

Fr.: instabilité à traines   

A type of instability that often occurs in fluids which are thermally stably stratified, but have an inhomogeneous composition. A well-known example, found in upper layers of the Earth's oceans, is → salt fingers. Similar fingering instabilities can occur in any other thermally stably stratified solution, provided the concentration of the slower-diffusing solute increases with height. The saturated state of this instability, → fingering convection, takes the form of tightly-packed, vertically-elongated plumes of sinking dense fluid and rising light fluid, and significantly enhances the vertical transport of both heat and chemical composition. The fingering instability occurs in stars within radiation zones that have an unstable mean → molecular weight  → gradient (μ gradient). This situation is often found as a result of material accretion onto a star by anything from a single or multiple planets, to material from a dust-enriched or debris accretion disk, or material from a more evolved companion. It also naturally arises in the vicinity of the → hydrogen shell burning in → red giant branch (RGB) stars, and in thin element-rich layers near the surface of intermediate-mass stars. The fingering instability initially takes the form of thin tubes, hence the name "finger," within which the fluid moves vertically. The tubes rapidly break down, however, as a result of parasitic shear instabilities that develop inbetween them, and the fingering instability eventually saturates into a state of homogeneous fingering convection where the typical aspect ratio of the eddies is closer to one (P. Garaud et al., 2015, arXiv:1505.07759).

finger; → -ing; → instability.

forward scattering
  پراکنش ِ پیش-سو   
parâkaneš-e piš-su

Fr.: diffusion en avant   

Scattering in which photons emerge from the → scattering medium travelling predominantly in the same direction as they entered. The → halos around the Sun and Moon in wet weather are caused by forward scattering by water droplets in the Earth's atmosphere. → backscattering.

forward; → scattering.

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