An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1330
continuum-driven wind
  باد ِ پیوستار‌زاد   
bâd-e peyvastârzâd

Fr.: vent induit par continuum   

The transfer of photon momentum to free electrons. The acceleration by → continuum emission can be given by: ac = (σ/m)(L*/4πR2c), where σ is the → Thomson scattering  → cross section, m is the mass per free electron, L* is → stellar luminosity, R* is radius, and c the → speed of light. The ratio of ac to the → surface gravity is ≅ 2 × 10-5L*/M*, with M* and L* in solar units. The atmosphere is is stable if ac very smaller than ggrav. If L* is above the → Eddington limit, the radiation pressure in the continuum leads to very heavy → mass loss and thus to expanding envelopes (K.S. de Boer & W. Seggewiss, 2008, Stars and Stellar Evolution, EDP Sciences).

continuum; → drive; → wind.

parband (#)

Fr.: contour   

The outline of a figure or body; the edge or line that defines or bounds a shape or object.

From Fr. contour "circumference, outline," from Italian contorno, from M.L. contornare "to go around," from L. → com- intens. prefix + tornare "to turn on a lathe," from tornus "lathe."

Parband, from par- "around" (Mid.Pers. pêrâ, O.Pers. pariy "around, about," Av. pairi "around, over," Skt. pari, cf. Gk. peri "around, about, beyond," L. per "through," PIE *per- "through, across, beyond") + band "belt, gridle, anything by which bodies are joined; tie, band," from bastan "to bind, shut," (Mid.Pers. bastan/vastan,Av./O.Pers. band- "to bind, fetter," banda- "band, tie," Skt. bandh- "to bind, tie, fasten," PIE *bhendh- "to bind," cf. Ger. binden, E. bind).

contour line
  خط ِ پربند   
xatt-e parband

Fr.: contour   

A line joining points of equal elevation or on a surface or points of equal intensity in a map.

contour; → line.

contour map
  نقشه‌ی ِ پربندی   
naqše-ye parbandi

Fr.: carte de contours   

A map showing the flux intensity variations over an extended object made up of → contour lines.

contour; → map.

pâd- (#)

Fr.: contre-   

A prefix meaning "against; contrary; opposing."

From L. contra "against," passed (via O.Fr.) into E. as → counter-.


Fr.: se contracter, contracter   

1) To become smaller, shorter, tighter, as a metal when cooled.
2) To reduce to smaller size by or as if by squeezing or forcing together, e.g. contract a muscle.
contraction, → gravitational contraction, → Kelvin-Helmholtz contraction, → length contraction, → Lorentz contraction, → vena contracta.

From M.E., from O.F., from L. contractus, p.p. of contrahere "to draw together," from → com- "together" + trahere "to draw."

Terengidan, variant taranjidan [Dehxodâ] "to contract, become rough and hard, to be squeezed, compressed," Borujerdi terengessa "cramped, tightly dressed," Malâyeri terengidan "to be tightly dressed, cramped in a garment," related to tarang "horse girth, a strap for fastening a load," Proto-Iranian *trng- "to pull tight, squeeze, compress;" PIE base *strenk- "to pull tight, twist; tight, narrow" (cf. L. stringere "to bind or draw tight;" Gk. strangein "to twist;" Lith. stregti "to congeal;" O.E. streccian "to stretch," streng "string;" Ger. stramm, Du. stram "stiff").


Fr.: contraction   

An act or instance of contracting; the quality or state of being contracted.
gravitational contraction, → Kelvin-Helmholtz contraction, → length contraction, → Lorentz contraction.

Verbal noun of → contract.

pâdguyi (#)

Fr.: contradiction   

1) The act of contradicting; assertion of the contrary or opposite.
2) Logic: A statement that is false under all circumstances.

M.E., from O.Fr. contradiction or directly from L. contradictionem "objection, counterargument," from contradicere, from contra dicere "to speak against," from → contra- "against" + dicere "to speak," akin to Pers. dis, → form.

Pâdguyi, literally "speaking against," from pâd, → counter-, + guyi, from goftan, → logic.

pâdguyâné (#)

Fr.: contradictoire   

Asserting the contrary or opposite; contradicting; inconsistent; logically opposite (

Adjective from → contradiction.


Fr.: contraste   

In an → image, the degree of distinction between areas with different → brightness levels; in other words, the → ratio of the brightness between light and → dark areas.

From Fr. contraster, from It. contrastare "stand out against," from V.L. *contrastare "to withstand," from L. → contra- "against" + stare "to stand," (cf. Pers. istâdan "to stand," O.Pers./Av. sta- "to stand, stand still; set," Skt. sthâ- "to stand," Gk. histemi "put, place, weigh," PIE base *sta- "to stand").

Pâdsâni, from pâd- "agianst," → contra- + sân "manner, semblance," variant sun, Mid.Pers. sân "manner, kind," Sogdian šôné "career" + -i noun suffix.

contravariant tensor
  تانسور ِ پادورتا   
tânsor-e pâdvartâ

Fr.: tenseur contravariant   

A tensor whose components are distinguished by → superscript indices.

contra-; + variant; → variance; → tensor.


Fr.: contribuer   

1) To give or supply (help, money, etc.) for a common purpose.
2) To provide (ideas, suggestions, work, etc.) for a common goal, such as an article, a book.

From L. contributus, p.p. of contribuere "to bring together, unite, collect," from → com- + tribuere "to pay, assign, allot," from tribus "tribe."

Hambâžidan, from ham- "together," → com-, + bâž "tribute, toll, impost," → distribute.


Fr.: contribution   

1) The act of contributing.
2) Something contributed.

Verbal noun of → contribute.

  همبز، همبرد   
hambaz, hambord (#)

Fr.: convection   

In general, mass motions within a → fluid resulting in transport and mixing of the properties of that fluid when the temperature gradient exceeds some critical value. Convection, along with → conduction and → radiation, is a principal means of → energy transfer. → Schwarzschild's criterion.

From L. convectionem "the act of carrying," from p.p. stem of convehere "to carry together," from → com- "together" + vehere "to carry," cf. Skt. vah- "to carry, lead," vahitra "vehicle," Av. vazaiti "to lead," Mid.Pers. waz-, wazidan "to carry away," Gk. oxos "chariot;" PIE base *wegh- "to go, carry, drive"

Hambaz, from ham- "together" + baz "to carry, move," → evection.
Hambord, from ham- "together," → com- + bord, from bordan "to carry," Mid.Pers. burdan, O.Pers./Av. bar- "to bear, carry," barəθre "to bear (infinitive)," Skt. bharati "he carries," Gk. pherein, L. fero "to carry," PIE base *bher- "to carry."

convection zone
  زنار ِ همبز   
zonâr-e hambaz

Fr.: zone de convection   

Same as → convective zone.


Fr.: convectif   

Of or relating to → convection.

convective cell
  یاخته‌ی ِ همبزی   
yâxte-y hambazi

Fr.: cellule convective   

A body of → fluid which transports energy through the → convection process.

convective; → cell.

convective cloud
  ابر ِ همبزی   
abr-e hambazi

Fr.: nuage convectif   

Meteorology: A cloud that owes its vertical development, and possibly its origin, to convection.

convective; → cloud.

convective core
  مغزه‌ی ِ همبزی   
maqze-ye hambazi

Fr.: cœur convectif   

The central region of a → massive star where → convection prevails due to steep gradient of temperature relative to pressure.

convective; → core.

convective envelope
  پوشه‌ی ِ همبزی   
puše-ye hambazi

Fr.: enveloppe convective   

1) A → convective zone situated beneath the surface of solar type stars.
2) Stellar models show that → massive stars also possess an outer convective envelope encompassing several percent of the stellar radius. Fast rotation amplifies the size of the convective envelope in → OB stars and developes anisotropic convective envelops (Maeder et al. 2008, A&A 479, L37).

convective; → envelope

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