An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1010
Pollux (β Geminorum)
Polluks (#)

Fr.: Pollux   

The brightest star in the constellation → Gemini despite its designation as β. Also known as HR 2990 and HD 62509. Pollux lies about 4 degrees apart from the blue star → Castor with which it has no physical connection. Pollux is an orange-red star with a → visual magnitude 1.14 (B - V = +1.00) located about 34 → light-years away. It is a → giant star of → spectral type K0 III, with a mass of 2 Msun, a radius of about 10Rsun, a luminosity of 43 Lsun, and an → effective temperature of 4666 K. Pollux has a large planet, → Pollux b, with a mass of at least 2.3 times the mass of Jupiter.

Pollux, Gk. Polydeucus is one of the "Heavenly Twins," brother to → Castor, sons of Leda and Zeus.

Pollux, loan from L., as above. It has a too long Ar. name: Al-Ra's-at-Tau'am-al-Mo'akhkhar (الرأس‌التوأم‌المؤخر) "the head of the posterior twin," translating the Gk. mythological figure.

Pollux b
  پولوکس b   
Polluks b

Fr.: Pollux b   

An → extrasolar planet orbiting the bright star → Pollux (β Gem). It lies approximately 34 → light-years away in the constellation → Gemini. Called also → Thestias, it has a mass of at least 2.30 → Jupiter mass, and orbits Pollux at a distance of about 1.64 → astronomical units once every 590 days.


poloidal magnetic field
  میدان ِ مغناتیسی ِ قطبی‌وار   
meydân-e meqnâtisi-ye qotbivâr

Fr.: champ magnétique poloïdal   

1) In → protoplanetary disk models, the magnetic field whose large-scale lines of force depart away from the → accretion disk, in the direction of the rotation axis.
2) In a → tokamak, the magnetic field produced by a current flowing in the → plasma vertically to the toroid plane. → toroidal magnetic field.

pole; → -oid; → magnetic field.

poloniom (#)

Fr.: polonium   

A radioactive chemical element; symbol Po. Atomic number 84; mass number of most stable isotope 209; melting point 254°C; boiling point 962°C.

The name derives from Poland, the native country of Marie Sklodowska Curie. It was discovered by Pierre and Marie Curie in 1898, from its radioactivity.

  بُل-، چند-   
bol- (#); cand- (#)

Fr.: poly-   

A prefix denoting "much, many."

From Gk. poly-, combining form of polus "much," cognate with L. plus, Pers. bol-, as below; from PIE base *pel- "to be full."

Bol- "much; very; many," as in examples bolkâmé "desirous" (literally "with much desire"), bolhavas, variant porhavas "very desirous, libidinous" (literally "with much lust"); variant of por "full, much, very," Mid.Pers. purr "full;" O.Pers. paru- "much, many;" Av. parav-, pauru-, pouru- "full, much, many," from par- "to fill;" PIE base *pelu- "full," from *pel- "to be full;" cf. Skt. puru- "much, abundant;" Gk. plethos "great number, multitude;" O.E. full.
Cand-, from cand "how many, how much; so many; several; some; much;" Mid.Pers. cand "how many?, so many; much; some;" O.Pers. yāvā "as long as;" Av. yauuant- [adj.] "how great?, how much?, how many?," yauuat [adv.] "as much as, as far as;" cf. Skt. yāvant- "how big, how much;" Gk. heos "as long as, until."


Fr.: polychromatique   

Having or exhibiting a variety of colors.

poly-; → chromatic.

polycyclic aromatic hydrocarbons (PAHs)
  هیدروکربورهای ِ اروماتیک ِ پلی‌سیکلیک، ~ ~ بُل‌چرخه‌ای   
hidrocarburhâ-ye aromâtik-e polisiklik, ~ ~ bol-carxe-yi

Fr.: hydrocarbures aromatiques polycycliques   

1) Chemistry: A family of → organic molecules composed of carbon and hydrogen atoms (→ hydrocarbons) in which → carbon atoms appear in multiple loops (polycyclic) with strong chemical → bonds that exist between them (aromatic). PAHs are formed during the incomplete burning of coal, oil and gas, garbage, or other organic substances like tobacco or charbroiled meat. As a pollutant, they are of concern because some compounds (benzo(a)pyrene) have been identified as tending to cause cancer.
2) Astro.: Strong → infrared emission features at 3.3, 6.2, 7.7, 8.6, and 11.2 microns, which are attributed to PAH molecules in the form of → dust grains with radii smaller than 10 Å. PAHs are common toward various sources characterized by a strong → ultraviolet radiation field (such as → active galaxies, → reflexion nebulae, → planetary nebulae, → H II regions). In particular, they trace the presence of → massive stars. The PAH features are thought to result from the fluorescent emission process of PAH molecules and ions excited by ultraviolet radiation of nearby stars. PAHs are likely produced by → photoevaporation of → very small grains.

poly-; → cyclic; → aromatic; → hydrocarbon.

  بل‌دادارباوری، چنددادارباوری   
bol-dâdâr-bâvari, cand-dâdâr-bâvari

Fr.: polydéisme   

A kind of → deism according to which multiple deities created the Universe, but do not interact with the physical world. → polytheism.

poly-; → deism.

candbar (#)

Fr.: polygone   

A one-dimensional closed figure consisting of a series of points, each of which is called a → vertex, and the line segments, called → sides, joining the vertices. Polygons of three sides are called → triangles, and of four sides → quadrilaterals.

poly- + → -gon.


Fr.: polyèdre   

1) Geometry: A three-dimensional figure formed by several → polygons.
2) A set P ⊆ ℜn is a polyhedron if there is a system of finitely many unequalities Ax ≤ b such that P = {x ∈ ℜn | Ax ≤ b}.

poly-; → hedron.


Fr.: 1) polynôme; 2) polynomial   

1) A mathematical expression involving a sum of powers in one or more variables multiplied by coefficients.
2) Consisting of or characterized by two or more terms or names.

From → poly- + (bi)nomial, contraction of → nominal.

polynomial equation
  هموگش ِ بلنامین   
hamugeš-e bolnâmin

Fr.: équation polynomiale   

An equation of the form a0 + a1x + a2x2 + ... + anxn, where a0 ... an are → real numbers and an≠ 0. Same as → algebraic equation.

polynomial; → equation.


Fr.: polisémie   

Diversity of meanings.

From N.L. polysemia, from L. polysemus "with many significations" (from Gk. polysemos, from → poly- + sem, from sema "sign," → semantic, + adj. suffix -os), + -ia.

Bolcemi, from bol, → poly-, + cem, → meaning, + noun suffix -i.

  بل‌یزدان‌باوری، چندیزدان‌باوری   
bol-yazdân-bâvari, cand-yazdân-bâvari

Fr.: polythéisme   

The doctrine of or belief in more than one god or in many gods ( → polydeism.

poly-; → theism.


Fr.: polytrope   

In astrophysics, a gaseous sphere in hydrodynamic equilibrium in which the pressure and density are related by the equation P = Kρ(n+1)/n at each point along the radius, where K is a constant and n is the → polytropic index. The constant K depends upon the nature of the polytrope. Before the advent of computing technology, the theory of polytropes played an important role in physically modeling the structure of stars. → Lane-Emden equation.

Polytrope, from → poly- + trope, from → -tropic.

Bolgašt, from bol-, → poly-, + gašt "change, alteration," → -tropic.


Fr.: polytropique   

1) Math.: Describing a function which has different values for one variable.
2) Thermodynamics: Pertaining to pressure and volume change that maintains specific heat. → polytropic process.

poly- + → -tropic.

polytropic change
  دگرشد ِ بُلگشتی، دگرش ِ ~   
degaršod-e bolgašti, degareš-e ~

Fr.: changement polytropique   

A change in the → pressure or → volume of a → gas in a → polytropic process.

polytropic; → change.

polytropic gas
  گاز ِ بُلگشتی   
gâz-e bolgašti

Fr.: gaz polytropique   

A gas capable of undergoing a → polytropic process.

polytropic; → gas.

polytropic index
  دیشن ِ بُلگشت   
dišan-e bolgašt

Fr.: index polytropique   

A number appearing in the equation describing a → polytropic process.

polytropic; → index.

polytropic process
  فراروند ِ بُلگشتی   
farâravand-e bolgašti

Fr.: processus polytropique   

A thermodynamic process that obeys the relation: PVn = C, where P is pressure, V is volume, n is any real number, called the → polytropic index, and C is a constant.
If n = 0, then P = C and it is an → isobaric process.
If n = 1, then for an → ideal gas PV = NkT = C and it is an → isothermal process.
If n = γ, → adiabatic index, then for an ideal gas it is an → adiabatic process.

polytropic; → process.

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