jofteš-e Russell-Saunders, jafsari-ye ~
Fr.: couplage Russell-Saunders
A coupling scheme of → electron configuration, used mainly for the lighter atoms with → atomic number less than 30. In an atom when changes in energy states are produced by the action of two or more electrons, the value of the total angular momentum of these electrons results from the coupling between the total → orbital angular momenta of the electrons and the total → spin angular momenta of the electrons. In this scheme the orbital angular momenta and spin angular momenta of electrons are added separately to give the total angular momentum L = Σi li and the total electron spin angular momentum S = Σi si. These are then added to give J = L + S. Also called → LS coupling. See also → jj coupling.
After Henry Norris Russell (1877-1957) and Frederick Albert Saunders (1875-1963), American astronomers (1925, ApJ 61, 38); → coupling.
In computer science, to increase the processing power of the same node/system by increasing its resources (CPU, RAM, etc.). This is a type of → vertical scaling opposite to → scale down. For example, instead of a machine with a CPU running at speed of X and having Y gigabytes of memory, use a machine with a CPU running at speed of 4X and a memory of 4Y gigabytes. See also → scale in, → scale out.
Fr.: groupe du Sculpteur
The nearest group of galaxies to our → Local Group, lying near the south Galactic pole at about 10 million → light-years distance. The Sculptor Group is dominated by five galaxies, four spiral (NGC 247, 253, 300, and 7793) and one irregular (NGC 55). The brightest of the five is NGC 253. The nearest galaxy in this group is NGC 55 which at a distance of 5 million light-years lies on the border of the Local Group.
Fr.: deuxième dragage
A → dredge-up process that occurs after core helium burning, in which the convective envelope penetrates much more deeply, pushing hydrogen burning shell into close proximity with the helium burning shell (→ first dredge-up). This arrangement is unstable and leads to burning pulses. The reason is that the hydrogen shell burns out until there is enough helium for the helium combustion to occur and all the helium is rapidly burnt. Afterward the hydrogen shell again burns outward and the process repeats.
To install and configure hardware and software on a computer.
Verb of → setup.
1) The process of connecting and preparing a software program, hardware
device, or computer to function properly. Setup is a file commonly called
"setup.exe" that is executed to begin installing a software program onto a
computer. See also → set up.
Barbešt, from prefix bar-, → on-.
From sextuple, from L. sext(us) "sixth," → six, + et
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.