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: 888
anomalous dispersion
  پاشش ِ ناسان   
pâšeš-e nâsân

Fr.: dispesrion anormale   

The phenomenon whereby the → refractive index of light in a medium changes rapidly with wavelength in the vicinity of an → absorption band. Hence the → dispersion curve of the substance shows marked deviations from → Cauchy's equation, in contrast with the behavior of → normal dispersion. On the shorter λ side of the absorption band the refractive index falls off more rapidly than required by Cauchy's equation representing values of n for visible light. On the long λ side of the absorption band the index is very high, decreasing at first rapidly and then more slowly as one goes beyond the absorption band.

anomalous; → dispersion.

anomalous luminosity effect
  اسکر ِ تابندگی ِ ناسان   
oskar-e tâbandegi-ye nâsân

Fr.: effet luminosité anormale   

Discrepant luminosity classes derived for the same → Am star when different criteria are used. Lore specifically, a luminosity criterion may indicate a → giant star, wheras another criterion indicates a → supergiant.

anomalous; → luminosity; → effect.

anomalous redshift
  سرخ-کیب ِ ناسان   
sorx-kib-e nâsân

Fr.: décalage anormal vers le rouge   

The high redshift of a quasar which is seemingly physically associated with a galaxy of low redshift.

anomalous; → redshift.

anomalous X-ray pulsar (AXP)
  پولسار ِ پرتوهای ِ ایکس ِ ناسان   
pulsâr-e pertwâ-ye iks-e nâsân

Fr.: pulsar X anormal   

A member of a small class of → X-ray pulsars with long rotation periods (6-12 seconds), short → spin-down times (~ 103-105 years), and → soft X-ray spectrum. AXPs show no evidence of being → X-ray binary systems. Their magnetic fields, as deduced from their spin-down rate, are the highest known, reaching 1013-1015 → gauss. AXPs are generally believed to be → magnetars.

anomalous; → X-ray; → pulsar.

anomalous Zeeman effect
  اُسکر ِ زیمن ِ ناسان   
oskar-e Zeeman-e nâsân

Fr.: effet Zeeman anormal   

The splitting of a spectral line into several components in the → Zeeman effect when the magnetic field is weak. The splitting is much more complex than in the normal effect. The number of components of the lines often considerably exceeds their number in the normal effect. Contrarily to the normal Zeeman effect, the anomalous effect cannot be explained by classical theory. The historically "anomalous" effect is accounted for by the inclusion of electron spin in the total angular moment. In fact the idea of electron spin was put forward (Uhlenbeck and Goudsmit, 1926) to explain the anomalous Zeeman effect.

anomalous; → Zeeman effect.

anomaly
  ناسانی   
nâsâni (#)

Fr.: anomalie   

In general, a deviation from the norm.
An angle that gives the position of an object in an elliptical orbit at any given time with respect to its primary. The true anomaly is the angle between the periapsis of an orbit and the object's current orbital position, measured from the body being orbited and in the direction of orbital motion. The mean anomaly is what the true anomaly would be if the object orbited in a perfect circle at constant speed.

Anomaly from → anomalous

Nâsâni, from nâ- negation suffix + sân "rule, law, custom" + -i noun maker suffix.

anonymous
  انام، بینام   
anâm, binâm

Fr.: anonyme   

Having an unknown or unacknowledged name. → anonymous object.

L. annymus, from Gk. annumos "nameless," from → an- "without" + onoma, onuma "name". Compare with L. nomen, Skt. nama, Av. nama, Mod. Pers. nâm, PIE *nomen "name".

Anâm, from Persian → a-, an- "without" + nâm "name," as above. Binâm, from bi- "without" + nâm.

anonymous object
  بر‌آخت ِ انام، ~ بینام   
barâxt-e anâm, ~ binâm

Fr.: objet anonyme   

An → astronomical object which has not been catalogued.

anonymous; → object.

ansa
  دستک   
dastak

Fr.: anse   

Plural form: ansae.
1) The "handles," or extremities, of → Saturn's rings as viewed from Earth.
2) The extremities of a → lenticular galaxy.

L. ansa "handle."

Dastak "handle," from dast "hand" (Mid.Pers. dast; O.Pers. dasta-; Av. zasta-; cf. Skt. hásta-; Gk. kheir; L. praesto "at hand;" Arm. jern "hand;" Lith. pa-žastis "arm-pit;" PIE *ghes-to-) + -ak suffix denoting relation, affinity, similarity.

ansatz
  آنزاتس   
ânzâts

Fr.: ansatz   

In physics and mathematics an a priori assumption that is used to establish the form of an equation or a system of equations. The ansatz, which is verified later by the result, is meant to facilitate the solution. → Bethe ansatz.

From Ger. Ansatz "attempt, approach, beginning."

antapex
  پادچکاد   
pâdcakâd

Fr.: antiapex   

The direction in the sky (in → Columba) away from which the Sun seems to be moving (at a speed of 19.4 km/s) relative to general field stars in the Galaxy.

Antapex from L. ant-, → anti- "against, opposite," + L. → apex "summit, peak, tip."

Pâdcakâd from pâd-, → anti- + cakâd "summit of a mountain; top, crown of the head, top of the forehead," from Mid.Pers. cakât "summit," → apex.

Antarctic
  دشترگان، جنوبگان   
Daštargân, Jonubgân (#)

Fr.: Antarctique   

The south polar area, south of latitude 66° 33' 8'' S.

Antarctic, from O.Fr. antartique, from M.L. antarcticus, from Gk. antarktikos "opposite the north," from → anti- "opposite" + arktikos, → arctic.

Daštargân, from daštar, → south, + -gân suffix indicating the direction.
Jonubgân, from jonub "south," from Ar. janub "south," + -gân, as above.

Antares (α Scorpii)
  کژدمدل، قلب‌العقرب   
Každom-del, Qalb-ol-Aqrab

Fr.: Antarès   

A red supergiant star (spectral type M1 Ib) in the constellation → Scorpius, lying about 500 → light-years from Earth. It has a dwarf massive companion (B3 V), which is a radio source.

Antares, in Gk. "rival of Mars," from Gk. → anti + Ares "the Gk. god of War, called Mars by the Romans". The comparison with the planet Mars is because they are both red in color and have the same brightness.

Každom-del "the heart of the Scorpion," from každom "scorpion + del "heart." Qalb-ol-'Aqrab "the heart of the Scorpion," from Ar. Qalb "heart + 'aqrab "scorpion".

antecedent
  پیشای، پیش‌آی   
pišây

Fr.: antécédent   

Logic: In a → conditional proposition, the → clause which follows if.

M.E., from from L. antecedentem, from antecedere "go before, precede," from ante- "before" + cedere "to yield, to go," → process.

Pišây, from piš "before," → pre-, + ây present stem of âmadan "to come," → process.

antenna
  آنتن   
ânten

Fr.: antenne   

1) General: A device or a set of wires that receives or sends out radio signals.
2) In radio astronomy, the major dish-like component or wired structure used to collect radio signals.

L. antenna "sail yard," the long yard that sticks up on some sails, of unknown origin, perhaps from PIE base *temp- "to stretch, extend." In this sense, it is a translation of Gk. keraiai "horns" (of insects).

Âten, from Fr. antenne, from L. as above.

antenna gain
  بهره‌ی ِ آنتن   
bahre-ye ânten

Fr.: gain d'antenne   

A measure of the directivity of a radio telescope. It is the ratio of the amount of power received in the direction the dish is pointing to the smaller amount of power from other directions in the sidelobes.

antenna; → gain.

antenna lobe
  لپ ِ آنتن   
lap-e ânten

Fr.: lobe d'antenne   

A three-dimensional section of the → radiation pattern ofa directional antenna, bounded by one or more cones of nulls or by regions of diminished irradiance.

antenna; → lobe.

antenna pattern
  الگوی ِ آنتن   
olgu-ye ânten

Fr.: diagramme de rayonnement   

The response of an antenna to incident radiation as a function of the direction of incidence of the radiation. A generic antenna pattern consists of a → main lobe and a number of smaller → side lobes. Also called → radiation pattern.

antenna; → pattern.

antenna temperature
  دما‌ی ِ آنتن   
damâ-ye ânten

Fr.: température d'antenne   

In radio astronomy, a measure of the power absorbed by the antenna. In an ideal, loss-free radio telescope, the antenna temperature is equal to the brightness temperature if the intensity of the received radiation is constant within the main lobe. → antenna; → temperature.

antenna; → temperature.

Antennae galaxies
  کهکشان‌ها‌ی ِ شاخکی   
kahkešânhâ-ye šâxak

Fr.: galaxies des Antennes   

The pair of colliding galaxies NGC4038 and NGC4039 and the long arcing insect-like "antennae" of luminous matter revealed by optical telescopes. The "antennae" are believed to have been produced by the collision between the galaxies that began about 100 million years ago and is still occurring. The Antennae Galaxies, about 60 million → light-years from Earth, lie in the constellation → Corvus.

Antennae, plural of → antenna; → galaxy.

Kahkešânhâ, plural of kahkešângalaxy; šâxak "insect antenna," from šâx "horn" (Mid.Pers šâk, cf. Skt. sakha- "a branch, a limb," Arm. cax, Lit. šaka, O.S. soxa, PIE *kakhâ "branch") + -ak suffix denoting relation, affinity, similarity (as in dastak, pos(tak, pas(mak, xarak, nâxonak, mus(ak, eynak);

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