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: 912
annual motion
  جنبش ِ سالانه   
jonbeš-e sâlâné

Fr.: mouvement annuel   

The annual apparent motion of the → Sun in the sky with respect to → fixed stars along the path called → ecliptic. The apparent annual motion is due to the → Earth's → revolution about the Sun. In the course of this motion, the Sun appears to shifts about 1° eastward per day.

annual; → motion.

annual parallax
  دیدگشت ِ سالانه   
didgašt-e sâlâné

Fr.: parallaxe annuelle   

The difference in position of a star as seen from the → Earth and → Sun, i.e. the angle subtended at a star by the mean → radius of the Earth's orbit around the Sun. Same as → heliocentric parallax. Because the Earth revolves around the Sun, we observe the sky from a constantly moving position in space. Therefore, we should expect to see an annual effect, in which the positions of nearby objects appear to oscillate back and forth in response to our motion around the Sun. This does in fact happen, but the distances to even the nearest stars are so great that we need to make careful observations with a telescope to detect it. The annual parallax of the nearest star, → Proxima Centauri, is 0.762 arcsec, which is too small for our → acuity of vision.

annual; → parallax.

annual variation
  ورتش ِ سالانه   
varteš-e sâlâné

Fr.: variation annuelle   

Generally, the variation of a quantity over a year. In particular the yearly change in the right ascension or declination of a star, produced by the combined effects of the precession of the equinoxes and the proper motion of the star.

annual; → variation.

annul
  آنولیدن   
ânulidan

Fr.: annuler   

(Especially of laws or other established rules, usages, etc.) to make void or null; abolish; cancel; invalidate (Dictionary.com).

M.E., from O.Fr. anuller, from L.L. annullare "to make to nothing," from L. → ad- "to" + nullum, neuter of nullus "nothing," → null.

Ânulidan, from prefix â- + nul, → null, + -idan infinitive suffix.

annular
  حلقه‌وار، حلقه‌ای   
halqevâr, halge-yi

Fr.: annulaire   

Having the form of a → ring.

From Fr. annulaire or directly from L. annularis "pertaining to a ring," from annulus, diminutive of anus "ring."

Halge-yi, halqevâr, adj. from halqé, → ring.

annular eclipse
  خورگرفت ِ حلقه‌وار   
xorgereft-e halqevâr

Fr.: éclipse annulaire   

A solar eclipse in which the Moon is close the → apogee and is, therefore, too small to cover the whole disk of the Sun, leaving a visible edge or ring of sunlight. An annular eclipse can last for 12m 30s at the most. See also → total eclipse.

annular; → eclipse.

annular-total eclipse
  خورگرفت ِ حلقه‌وار-هماک   
xorgereft-e halqevâr-hamâk

Fr.: éclipse annulaire-totale   

A solar eclipse that has both annular and total phases. Same as → hybrid eclipse.

annular; → total; → eclipse.

annularity
  حلقه‌واری   
halqevâri

Fr.: annularité   

The maximum phase of an → annular eclipse during which the Moon's entire disk is seen silhouetted against the Sun. Annularity is the period between second and → third contact during an annular eclipse. It can last from a fraction of a second to a maximum of 12 minutes 29 seconds (F. Espenak, NASA).

annular; → -ity.

anode
  آنود   
ânod (#)

Fr.: anode   

An → electrode from which a stream of → electrons leaves, as in an electron tube or electrolytic cell. → cathode.

From Gk. anodos "way up," from → ana- "up" + hodos "way."

Ânod, loanword from anode as above.

anomalistic month
  ماه ِ پیرازمینی   
mâh-e pirâzamini

Fr.: mois anomalistique   

The time interval of 27.554 551 days (27d 13h 18m 33.2s), on average, between two successive passages of the Moon through the → perigee of its orbit.

Anomalistic from → anomaly.

Pirâzamini from pirâzamin, → perigee.

anomalistic year
  سال ِ پیراهوری   
sâl-e pirâhuri

Fr.: année anomalistique   

Anomalistic from → anomaly.

Pirâhuri from pirâhur, → perihelion.

anomalous
  ناسان   
nâsân

Fr.: anormal   

Deviating from the normal or common order, form, or rule. → anomaly.

From Gk. anomalos "uneven, irregular," from → an- "not" + homalos "even," from homos "same".

Nâsân, from Pers. nâ- "not" + sân "rule, custom, law, fashion," literally "out of rule".

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.

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