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: 1965 Search : ion
adsorption
  برشم   
baršam

Fr.: adsorption   

A process in which a layer of atoms or molecules of one substance forms on the surface of a solid or liquid. → absorption, → desorption, → sorption.

Adsorption from ad- "to" + sorption, from L. sorbere "to suck," → absorption.

Baršam, from bar- "on, upon" + šam "to drink, sip," → absorption.

advance of perihelion
  پیشرفت ِ پیراهور   
pišraft-e pirâhur

Fr.: avance du périhélie   

The slow rotation of the major axis of a planet's orbit in the same direction as the revolution of the planet itself, due mainly to gravitational interactions with other planets. The perihelion of the planet Mercury advances about 9'.6 per century. The bulk of the advance was accounted by perturbations from other planets. However, a remaining small advance, by 43'' per century, was eventually explained as an effect predicted by Einstein's theory of → general relativity. In the case of close binary stars, the advance of pericenter may additionally be caused by mass transfer and the stars' distorted (elliptical) shapes. Advance of perihelion (or pericenter) is also known as → apsidal motion.

Advance, from O.Fr. avancer "move forward," from V.L. *abantiare, from L.L. abante "from before," from ab- "from" + ante "before," PIE *ant- "front, forehead;" → perihelion.

Pišraft "advance," from piš "forward; in front; before," Mid.Pers. peš + raft "going; walk, travel," from raftan "to go."

advection
  پهنبز   
pahnbaz

Fr.: advection   

1) Geology: The process of transport of a quantity by the velocity field due to the movement of a fluid. Advection differs from → convection, which describes thermally driven circulation.
2) Meteorology: The predominantly horizontal, large-scale motions of the atmosphere. In contrast, convection describes the predominantly vertical, locally induced motions.

From L. advecti "act of conveying," from advectus, past participle of advehere "to carry," from ad-, "to" + vehere "to carry, bring;" Skt. vah-, vahati "to carry, conduct, guide," Av. vaz-, vazaiti "to guide, lead"; PIE *wegh- "to go, transport in a vehicle".

Pahnbaz from pahn "flat, wide, → broad," + baz "to carry," → evection.

advection term
  ترم ِ پهنبز   
tarm-e pahnbaz

Fr.: terme d'advection   

The first term on the right side in the → induction equation.

advection; → term.

affine combination
  میازش ِ کروَن   
miyâzeš-e karvan

Fr.: combinaison affine   

A linear combination of vectors in which all the vector coefficients add up to one.

affine; → combination.

affine transformation
  ترادیس ِ کروَن   
tarâdis-e karvan

Fr.: transformation affine   

Any → transformation preserving → collinearity.

affine; → transformation.

affirmation
  بردش   
bardeš

Fr.: affirmation   

The act of affirming or something affirmed.

Verbal noun of → affirm.

agglomeration
  برگلمش   
bargolemeš

Fr.: agglomération   

1) A jumbled cluster or mass of varied parts.
2) The act or process of agglomerating (Dictionary.com).

Verbal noun of → agglomerate.

agitation
  ژیلش   
žileš

Fr.: agitation   

The act or process of agitating; state of being agitated. → thermal agitation.

Verbal noun of → agitate.

Alfvenic fluctuation
  افتاخیز ِ آلفونیک   
oftâxiz-e Alfvenik

Fr.: fluctuation alfvénique   

Large amplitude fluctuations in the → solar wind with properties resembling those of → Alfvén waves. A fluctuation is said to be Alfvénic if the following relationship between the velocity fluctuations (Δv) and magnetic field fluctuations (ΔB) is satisfied: Δv = ± ΔB/(μ0ρ)1/2. Also called Alfvénicity.

Alfvén wave; → fluctuation.

Alfvénic fluctuation
  افتاخیز ِ آلفونیک   
oftâxiz-e Alfvenik

Fr.: fluctuation alfvénique   

Large amplitude fluctuations in the → solar wind with properties resembling those of → Alfvén waves. A fluctuation is said to be Alfvénic if the following relationship between the velocity fluctuations (Δv) and magnetic field fluctuations (ΔB) is satisfied: Δv = ± ΔB/(μ0ρ)1/2. Also called Alfvénicity.

Alfvénic; → fluctuation.

algebraic equation
  هموگش ِ جبری   
hamugeš-e jabri

Fr.: équation algébrique   

An equation in the form of P = 0, where P is a → polynomial having a finite number of terms.

algebra; → equation.

algebraic function
  کریای ِ جبری   
karyâ-ye jabri

Fr.: fonction algébrique   

A function expressed in terms of → polynomials and/or roots of polynomials. In other words, any function y = f(x) which satisfies an equation of the form P0(x)yn + P1(x)yn - 1 + ... + Pn(x) = 0, where P0(x), P1(x), ..., Pn(x) are polynomials in x.

algebraic + → function.

allocation
  تسک   
tesk

Fr.: allocation   

The act of allocating; the state of being allocated.

Verbal noun of → allocate.

Alnilam (ε Orionis)
  نظام، نظام‌الجوزا   
Nezâm, Nezâm-ol-Jowzâ

Fr.: Alnilam   

The central and brightest of the three stars in → Orion's Belt and the fourth brightest in the whole of → Orion. Alnilam is a blue-white → supergiant of → spectral type B0 Iae with a → visual magnitude of 1.70 and a → luminosity of 375,000 times the → solar luminosity. It lies at about 1,340 → light-years.

Alnilam, from Ar. An-Nizam al-Jawza' (النظام‌الجوزاء) "the Orion's arrangement (of pearls, beads)," from nizam "arrangement" + Jawza' "Orion".

Alnitak (ζ Orionis)
  نطاق، نطاق‌الجوزا   
Netâq, Netâq-ol-Jowzâ

Fr.: Alnitak   

The left hand or easternmost star in → Orion's Belt, which is the fifth brightest in the whole of → Orion with a → visual magnitude of 1.79. Alnitak is a wide visual binary system consisting of components ζ Ori A (HR 1948) and ζ Ori B (HR 1949), currently separated by ~ 2''.4. ζ Ori A is a → close binary system comprising Alnitak Aa and Alnitak Ab. Aa is a hot → blue supergiant of → spectral type O9.5 Iab with an → absolute magnitude of -6.0 and an → apparent magnitude of 2.08. Its mass is estimated as being up to 33 times as massive as the Sun and to have a diameter 20 times greater. It is some 250,000 times more luminous than the Sun, with a surface temperature of about 30,000 K. It is the brightest star of class O in the night sky. Alnitak Ab is a blue → subgiant of spectral type B1 IV with an absolute magnitude of -3.9, an apparent magnitude of 4.3, and a mass of 14 Msun. Ab revolves around Ab with a period of 2,687 days. The system has a 4th magnitude companion, Alnitak B, nearly 3 arc-seconds distant. It is a B0 III type star which orbits Alnitak A every 1,500 years. Alnitak is associated with the → emission nebula  → IC 434 containing the → Horsehead Nebula.A much fainter fourth component, ζ Ori C, is located about 57'' away from ζ Ori Aa (C. A. Hummel et al., 2013, A&A 554, A52, arXiv:1306.0330).

Alnitak, from Ar. An-Nitaq al-Jawza' (النطاق‌الجوزاء) "Orion's Belt," from nitaq "belt" + Jawza "Orion."

alpha emission
  گسیل ِ آلفا   
gosil-e âlfâ

Fr.: émission alpha   

The release of → alpha particles at high velocity from an atom's nucleus as it undergoes radioactive transformation.

alpha; → emission.

alteration
  دگرگونی، دگرگونش   
degarguni, degarguneš

Fr.: altération   

1) The act or process of altering; the state of being altered.
2) The result of altering.

Verbal noun of → alter.

alternation
  پیوارش   
peyvâreš

Fr.: alternance   

General: Successive change from one thing or state to another and back again.
The process of periodically varying a voltage from zero to a maximum, back to zero, to a minimum, and then to zero.

Alternation, noun from → alternate.

aluminizing, aluminization
  آلومینیوم اندود   
âluminiom andud (#)

Fr.: aluminisation   

The process by which the coating of aluminium is deposited on a telescope mirror.

Verbal noun of → aluminize.


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