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superbubble abar-tangol Fr.: superbulle A cavity hundreds of light-years across filled with a hot gas blown into the interstellar medium by multiple supernovae and stellar winds. Examples are the Local Bubble in the Orion Arm of the Milky Way and the N44 Superbubble in the Large Magellanic Cloud. |
supercluster abar-xušé Fr.: superamas 1) An aggregation of clusters of galaxies (→ galaxy cluster).
Superclusters are typically about one hundred million (108)
→ light-years in diameter and
contain tens of thousands of galaxies. Some examples are the
→ Local Supercluster,
→ Centaurus supercluster,
→ Laniakea supercluster,
→ Perseus-Pisces supercluster→ Shapley supercluster→ Virgo supercluster. |
superclustering abar-xuše bandi Fr.: Grouping of galaxies in supercluster structure. → super-; → clustering |
superconductivity abar-hâzandegi 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 |
superconductor abar-hâzandé Fr.: superconducteur A material which shows almost perfect conductivity at temperatures approaching absolute zero. |
supercooling abar-sardeš 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. |
supercritical abar-paržani Fr.: supercritique 1) Thermodynamics: Describing a condition in which a substance has
a temperature or pressure above its critical value of temperature or pressure. |
supercritical fluid 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. |
superfluid abar-šâré 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. |
superfluidity abar-šâregi 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. |
supergalactic abarkahkašâni Fr.: supergalactique Of or pertaining to a system composed of nearby groups and clusters of galaxies in the → local Universe. Se also → galaxy cluster. |
supergalactic coordinate system 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 varunâ-ye abarkahkašâni Fr.: latitude supergalactique → supergalactic coordinate system. → supergalactic; → latitude. |
supergalactic longitude derežnâ-ye abarkahkašâni Fr.: longitude supergalactique → supergalactic coordinate system. → supergalactic; → longitude. |
supergalactic plane 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. |
supergiant abar-qul 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. |
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 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 boxâr-e abar-garmidé Fr.: vapeur surchauffée A vapor that has been heated above its boiling point temperature corresponding to the pressure. |
superheating 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. |
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