An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 998
polar orbiting satellite
  ماهواره با مدار ِ قطبی   
mâhvâré bâ madâr-e qotbi

Fr.: satellite en orbite polaire   

A satellite that revolves around the Earth in an almost north-south orbit, passing close to both poles. The orbits are sun synchronous, allowing the satellite to cross the equator at the same local time each day. These satellites orbit at a height of 830-880 km and take about 100 minutes to complete a turn around the Earth.

polar; → orbit; → satellite.

polar plume
  پرک ِ قطبی   
parrak-e qotbi

Fr.: plume polaire   

A coronal feature of the Sun, which appears as long, thin streamers that project outward from the Sun's north and south poles

polar; → plume.

polar wind
  باد ِ قطبی   
bâd-e qotbi

Fr.: vent polaire   

1) The → solar wind occurring at high latitudes during low → solar activity as a fast (around 750 km s-1) and relatively steady flow. A remarkable feature of the polar wind is the ubiquitous presence of an intense flow of → Alfvénic fluctuations.
2) One of the two main wind components in → B[e] stars. The pole is hotter than the equator due to the → gravity darkening effect leading to a relatively fast, low-density wind driven by Fe IV lines. The other component is the → equatorial wind. The mechanism put forward to explain this wind morphology is the rotationally induced → bistability mechanism.
3) An extremely cold wind blowing from the north or south polar regions of the Earth.

polar; → wind.

polarimetry
  قطبش‌سنجی   
qotbešsanji

Fr.: polarimétrie   

The measurement of the → polarization state of light, usually through the use of a polarimeter.

From polari, from → polarization + → -metry.

Polaris
  ستاره‌ی ِ قطبی، جدی، میخ ِ گاه   
setâre-ye qotbi, jodey, mix-e gâh

Fr.: étoile polaire   

A triple star system lying at about 430 light-years from the Earth. Polaris A (visual magnitude about 2) is a pulsating variable star of type Cepheid. It is a hot, blue F7 giant or supergiant star having a luminosity about 2400 times that of the Sun. Polaris B (visual magnitude 8.2), was first noticed by William Herschel in 1780; it is separated from A by 18.5 arc sec, corresponding to approximately 2000 AU. The close companion Ab is only 0.06 arc sec, or about 7 AU, from Polaris A. Also called the → pole star.

Mod.L. short for stella polaris "the pole star," → polar.

Setâre-ye qotbi "polar star," from setâré, → star, + qotbi, → polar. Jodey, from Ar. Judaiy. Mix-e gâh Mid.Pers. name of the star, literally "the nail (peg) of time," from mix "nail, peg" (Mid.Pers. mêx "peg, nail;" O.Pers. mayūxa- "doorknob;" cf. Skt. mayūkha- "peg for stretching the woof") + gâh"time; place" (Mid.Pers. gâh, gâs "time;" O.Pers. gāθu-; Av. gātav-, gātu- "place, throne, spot;" cf. Skt. gâtu- "going, motion; free space for moving; place of abode;" PIE *gwem- "to go, come").

polarity
  قطبیگی   
qotbigi

Fr.: polarité   

1) Physics: The condition, in a system, of having opposite characteristics at different points, especially positive or negative with respect to electric charge or magnetic properties.
2) Chemistry: A property of a molecule caused by unsymmetrical charge distribution.

From → polar + → -ity.

polarity epoch
  زیمه‌ی ِ قطبیگی   
zime-ye qotbigi

Fr.: époque de polarité   

The time during which the Earth's magnetic field was of a single polarity; an interval of time between reversals of Earth's magnetic field.

polarity; → epoch.

polarity event
  رویداد ِ قطبیگی   
ruydâd-e qotbigi

Fr.: événement de polarité   

A specific event in the history of Earth's magnetic field. Usually used in reference to a specific → polarity reversal.

polarity; → event.

polarity reversal
  وارونش ِ قطبیگی، واگردانی ِ ~   
v âruneš-e qotbigi, vâgardâni-ye ~

Fr.: inversion de polarité   

1) A change in the → polarity of Earth's magnetic field in which the north magnetic pole becomes the south magnetic pole and vice versa. Also known as geomagnetic reversal or magnetic reversal. Earth's magnetic field has reversed many times in the past and the time intervals between these changes are known as → polarity epochs.
2) The change in the polarity of the → solar magnetic field with the ending of each → solar activity cycle so that the North magnetic pole becomes the South and vice versa.

polarity; → reversal.

polarizable
  قطبش‌پذیر   
qotbeš-pazir

Fr.: polarisable   

Able to be polarized.

polaize; → -able.

polarization
  قطبش   
qotbeš (#)

Fr.: polarisation   

1) Optics: A process or state in which the directions of the electric or magnetic fields of an → electromagnetic radiation change in a regular pattern. Light can be polarized by a variety of ways, involving the following processes: reflection, transmission, double refraction, and scattering. See also → unpolarized light; → linear polarization; → circular polarization; → elliptical polarization. The study of the polarization of light from astronomical sources can yield unique information in particular related to the properties of magnetic fields.
2) Electricity: A process or state in which the → dipole moments of → polar molecules in a → dielectric material get aligned under the action of an external electric field. Actually thin layers of bound charges with opposite signs appear on the surfaces of the dielectric.
3) Electricity: The accumulation of ions, produced during electrolysis, on the electrodes of a cell, increasing the resistance of the cell.

Verbal noun of → polarize.

polarization angle
  زاویه‌ی ِ قطبش   
zâviye-ye qotbeš (#)

Fr.: angle de polarisation   

Same as → polarizing angle and → Brewster angle.

polarization; → angle.

polarization charge
  بارِ قطبش   
bâr-e qotbeš

Fr.:   

Same as → bound charge.

polarization; → charge.

polarization degree
  درجه‌ی ِ قطبش   
daraje-ye qotbeš (#)

Fr.: degré de polarisation   

degree of polarization.

polarization; → degree.

polarization fraction
  برخه‌ی ِ قطبش   
barxe-ye qotbeš

Fr.: fraction de polarisation   

The ratio expressed by P = (Ipar - Iper) / (Ipar + Iper), where Ipar and Iper are the light intensities with the electric field vector respectively parallel and perpendicular to the incident beam.

polarization; → fraction.

polarize
  قطبیدن   
qotbidan (#)

Fr.: polariser   

To cause → polarization. To undergo polarization.

Infinitive of → polarization.

polarized
  قطبیده   
qotbidé (#)

Fr.: polarisé   

Of or pertaining to a medium or physical phenomenon that exhibits → polarization.

P.p. of → polarize.

polarized light
  نور ِ قطبیده   
nur-e qotbidé (#)

Fr.: lumière polarisée   

Electromagnetic radiation in the optical region which has undergone → polarization.

Past participle of → polarize; → light.

polarizer
  قطبنده   
qotbandé (#)

Fr.: polariseur   

An optical device capable of transforming natural light into polarized light, usually by selective transmission of polarized rays.

Agent noun of → polarize.

polarizing angle
  زاویه‌ی ِ قطبش   
zâviye-ye qotbeš (#)

Fr.: angle de polarisation   

The angle of → incidence for which the reflected light is completely polarized. Also called the → Brewster angle and → polarization angle. See also → Brewster's law.

Polarizing, adj. of → polarize; → angle.

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