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.
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.
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.
Fr.: latitude supergalactique
Fr.: longitude supergalactique