Fr.: superamas de Shapley
The richest → supercluster of galaxies in the nearby → Universe at a → redshift going from z ~0.03 to z ~0.05 (680 million → light-years), and extending over several square degrees on the plane of the sky. It lies behind the → Centaurus supercluster. Also called the Shapley concentration, it is made up of 25 → galaxy clusters with a total mass of about 1016→ solar masses. At the core of the Shapley supercluster is a remarkable complex formed by several rich clusters of galaxies from the → Abell catalog; the central and most massive of them is A3558.
Fr.: groupe d'espace
Set of operations (rotation about an axis, reflection across a plane, translation, or combination of these) which when carried out on a periodic arrangement of points in space brings the system of points to self-coincidence.
The word group comes from the mathematical notion of a group.
jafsari-ye espin-madâr, jofteš-e ~
Fr.: couplage spin-orbite
1) Astro.: A relationship between the orbital period of one body around another
and its rotational period on its axis. The relationship results from tidal forces
between the two bodies. For example, the rotation period of the Moon equals its revolution
period around the Earth.
Fr.: pleine lune de périgée
Same as → perigee full Moon.
super star cluster (SSC)
Fr.: super amas stellaire
A group of hundreds to thousands of very young stars packed into an unbelievably small volume of a few parsecs in size. These objects represent the youngest stage of → massive star cluster evolution yet observed. The most massive and dense SSCs, with ages less than 106 years, may be proto globular clusters. SSCs are thought to dissolve within 10 million years and merge into the field star population.
A prefix occurring originally in loanwords from Latin, with the basic meaning "above, beyond."
L. adverb and preposition super "above, over, on the top (of), beyond, besides, in addition to," from PIE base *uper "over," cognate with Pers. abar-, as below.
Mid.Pers. abar (Mod.Pers. bar- "on, upon, up"); O.Pers. upariy "above; over, upon, according to;" Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-, as above; O.H.G. ubir "over."
Fr.: étoile super-canonique
super-Chandrasekhar SN Ia
abar-now-axtar-e gune-ye Ia-ye abar-Chandrasekhar
Fr.: supernova de type Ia super-Chandrasekhar
A superluminous → Type Ia supernova which is characterized by a bright → light curve peak, a slow light curve evolution during the photospheric phase, and moderately low ejecta velocities. Modeling suggests ejecta masses far in excess of the → Chandrasekhar limit of mass for non-rotating → white dwarfs and the production of about 1.5 Msun of 56Ni. This precludes the interpretation of these events as thermonuclear explosions of Chandrasekhar-mass white dwarfs.
An → extrasolar planet more massive than the Earth but less massive than 10 → Earth masses. The first discovered super-Earth orbits an M4 V star named GJ 876. Its estimated mass is 7.5±0.7 Earth masses and it has an orbital period of 1.94 days. It is close to the host star, and the surface temperature is calculated to lie between 430 and 650 K (Rivera et al. 2005, ApJ 634, 625).
Fr.: vent super-Eddington
Fr.: étoile très riche en métaux
superadiabatic temperature gradient
zine-ye damâ-ye abar-bidarrow
Fr.: gradient de température super-adiabatique
A condition in which there is an excess of the actual temperature gradient over the → adiabatic temperature gradient corresponding to the same pressure gradient. A region with superadiabatic temperature gradient is convectively unstable. → Hayashi forbidden zone.
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.
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.
Grouping of galaxies in supercluster structure.
The phenomenon in which certain materials, when cooled to a sufficiently low temperature, lose all resistance to the flow of electricity.
A material which shows almost perfect conductivity at temperatures approaching absolute zero.
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.
1) Thermodynamics: Describing a condition in which a substance has
a temperature or pressure above its critical value of temperature or pressure.
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.