An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 251 Search : up

Fr.: superconductivité   

The phenomenon in which certain materials, when cooled to a sufficiently low temperature, lose all resistance to the flow of electricity.

super-; → conductivity


Fr.: superconducteur   

A material which shows almost perfect conductivity at temperatures approaching absolute zero.

super-; → conductor.


Fr.: surfusion   

The process by which a liquid or a gas is cooled below the temperature at which a → phase transition should occur. For example, water can be cooled well below the → freezing point without freezing (as often happens in the upper atmosphere). The introduction of an → impurity or surface can trigger freezing.

super-; → cooling.


Fr.: supercritique   

1) Thermodynamics: Describing a condition in which a substance has a temperature or pressure above its critical value of temperature or pressure.
2) Nuclear physics: Of or relating to an arrangement of → fissile material where more neutrons are being produced than are wasted and escape.

super-; → critical.

supercritical fluid
  شاره‌ی ِ ابر-پرژنی   
šârre-ye abar-paržani

Fr.: fluide supercritique   

A fluid that is at a temperature and pressure above its thermodynamic critical point. In these conditions the substance acquires unique characteristics of density and mobility. Supercritical fluids exist deep inside some planets; for example, there is supercritical water deep inside the Earth.

supercritical; → fluid.


Fr.: superfluide   

A → fluid that exhibits frictionless flow, very high heat → conductivity, and other unusual physical properties. For example, → liquid helium at the temperature about 2.17 K (→ lambda point) becomes a zero → viscosity fluid which will move rapidly through any pore in the apparatus. See also → helium II.

super-; → fluid


Fr.: superfluidité   

The phenomenon occurring in → liquid helium (→ helium I) cooled below the → lambda point temperature of 2.17 K, whereby it flows freely with no measurable → friction and → viscosity.

super-; → fluidity.


Fr.: supergalactique   

Of or pertaining to a system composed of nearby groups and clusters of galaxies in the → local Universe. Se also → galaxy cluster.

super-; → galactic.

supergalactic coordinate system
  راژمان ِ هماراهای ابرکهکشانی   
râžmân-e hamârâhâ-ye abarkahkašâni

Fr.: système des coordonnées supergalactiques   

A spherical → coordinate system in which the → equator is the → supergalactic plane. Supergalactic longitude, SGL, is measured → counterclockwise from direction l = 137.37 deg, b = 0 deg (between 0 and 360 deg). The zero point for supergalactic longitude is defined by the intersection of this plane with the → Galactic plane. In the → equatorial coordinate system (J2000) this is approximately 2.82 h, +59.5 deg. Supergalactic latitude, SGB, is measured from the supergalactic plane, positive northward and negative southward. The North Supergalactic Pole (SGB=90 deg) lies at galactic coordinates l = 47.37 deg, b = +6.32 degrees, corresponding to the equatorial coordinate system (J2000) 18.9 h, +15.7 deg.

supergalactic; → coordinate; → system.

supergalactic latitude
  ورونای ِ ابرکهکشانی   
varunâ-ye abarkahkašâni

Fr.: latitude supergalactique   

supergalactic coordinate system.

supergalactic; → latitude.

supergalactic longitude
  درژنای ِ ابرکهکشانی   
derežnâ-ye abarkahkašâni

Fr.: longitude supergalactique   

supergalactic coordinate system.

supergalactic; → longitude.

supergalactic plane
  هامن ِ ابرکهکشانی   
hâmon-e abarkahkašâni

Fr.: plan supergalactique   

The symmetry plane of the → Local Supercluster, where density of galaxies in our environment is the largest. The plane passes through the → Virgo cluster of galaxies, about which many of the brightest galaxies in the sky are concentrated. The supergalactic plane was recognized by Gérard de Vaucouleurs (1918-1995) in 1953 from the  → Shapley-Ames catalogue.

supergalactic; → plane.


Fr.: supergéante   

A star with maximum intrinsic brightness and low density. The radius of a supergiant can be as large as 1000 times that of the Sun. See also → blue supergiant; → red supergiant; → yellow supergiant.

super-; → giant

supergiant B[e] star (sgB[e])
setâre-ye B[e]-ye abarqul

Fr.: étoile B[e] supergéante   

A highly luminous → B[e] star with a luminosity greater than 104L_sun. A number of such objects exist in the → Magellanic Clouds, e.g. LMC R126, R66, SMC R4, and R50. A likely example in our Galaxy is MWC 300.

supergiant; → B[e] star.

supergranulation cell
  یاخته‌ی ِ اَبَر-دانه‌بندی   
yâxte-ye abar-dâne-bandi

Fr.: cellule de supergranulation   

One of a number of large convective cells (about 15,000-30,000 km in diameter) in the solar photosphere, distributed fairly uniformly over the solar disk, that last longer than a day.

super-; → granulation; → cell.

superheated vapor
  بخار ِ اَبَر-گرمیده   
boxâr-e abar-garmidé

Fr.: vapeur surchauffée   

A vapor that has been heated above its boiling point temperature corresponding to the pressure.

super-; → heat; → vapor.

  اَبَر-گرمش، اَبَر-گرمایش   
abar-garmeš, abar-garmâyeš

Fr.: surchauffe   

The process in which a liquid is heated to a temperature higher than its boiling point, without boiling. Superheating is achieved by heating a homogeneous substance in a clean container, free of nucleation sites.

super-; → heating.

superheterodyne receiver
  گیرنده‌ی ِ اَبَر-هترودینی   
girande-ye abar-heterodini (#)

Fr.: récepteur superhétérodyne   

A radio receiver which uses the → superheterodyne technique.

super-; → heterodyne; → receiver.

superheterodyne technique
  تشنیک ِ اَبَر-هترودین   
tašnik-e abar-heterodin

Fr.: technique superhétérodyne   

The technique used in a radio receiver in which the frequency of an incoming signal is changed by adding it to a signal generated within the receiver to produce fluctuations or beats of a frequency equal to the difference between the two signals. See also → mixer.

superheterodyne receiver; → technique.


Fr.: superion   

An ion which is responsible for the existence of a strong → P Cygni profile observed in many early O stars. Since the → effective temperature of the star is too low to produce such an ion appreciably, the ion is termed a superion. For example, the ion O5+ which is at the origin of a strong O VI λλ1031, 1038 P Cygni profile observed in many O stars. Similarly, the lines due to N V λλ1238, 1242 belong to the superion category, while in later spectral types C IV λλ1548, 1552 also falls into this category. Initial modeling of the → ultraviolet line superions assumed the → stellar winds were smooth and homogeneous. However it is now generally accepted that the winds are (→ clumped wind), and this can have a profound influence on the formation of the superion profiles. We know that the strength of lines due to the superions is strongly influenced by the → interclump medium. Indeed, the interclump medium may be more important for producing the lines than are the clumps -- this is simply a consequence of the higher ionization in the interclump medium which occurs because of its lower density (see D. John Hillier, 2020,, and references therein).

super-; → ion.

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