A suffix denoting spatial or temporal direction, as specified by the initial element. Also -wards (Dictionary.com).
-su, → direction.
Fr.: après, ensuite, plus tard
At a later or subsequent time; subsequently.
Fr.: naine d'Antlia
A → dwarf spheroidal galaxy located about 4.3 million → light-years from. Earth. It is a very faint object, with an apparent magnitude of 16.2. The galaxy was not discovered until 1997. (PGC 29194) The Antlia Dwarf lies on the outer rim of the Local Group of galaxies, possibly even beyond it, and there is evidence suggesting that it is tidally interacting with another small galaxy, NGC 3109, in the → Hydra constellation.
Fr.: logiciel d'application
A software with a specific function, such as a word processor or game. Contrast with operating system software.
Having knowledge; conscious; informed; alert. → awareness.
M.E., variant of iwar, O.E. gewær; cf. O.S. giwar, M.Du. gheware, O.H.G. giwar, Ger. gewahr.
Âgâh "aware, knowing," related to negâh "look, attention;" Mid.Pers. âkâh; Av. ākas- "to look;" Proto-Iranian *kas- "to look, appear;" cf. Skt. kāś- "to become visible, appear;" Gk. tekmar, tekmor "sign, mark;"
The state or condition of being aware; having knowledge; consciousness
Fr.: en arrière
1) Toward the back or rear.
Fr.: effet de rétro-réchauffement
A sort of → greenhouse effect in → stellar atmospheres where the deeper layers heat up due to overlying → opacity. The presence of numerous → bound-bound opacities of → metals amplifies the → scattering of → photons, in particular their → backscattering, forcing the → temperature to increase in order to conserve the radiation flux and the transport of energy from the interior to the outer parts of the atmosphere.
blue compact dwarf galaxy
kahkešân-e kutule-ye âbi-ye hampak
Fr.: galaxie naine bleue compacte
An small → irregular galaxy undergoing → violent star formation activity. These objects appear blue by reason of containing clusters of hot, → massive stars which ionize the surrounding interstellar gas. They are chemically unevolved since their → metallicity is only 1/3 to 1/30 of the solar value. Same as → H II galaxy.
Fr.: naine brune
A star-like object whose mass is too small to sustain → hydrogen fusion in its interior and become a star. Brown dwarfs are → substellar objects and occupy an intermediate regime between those of stars and giant planets. With a mass less than 0.08 times that of the Sun (about 80 → Jupiter masses), nuclear reactions in the core of brown dwarfs are limited to the transformation of → deuterium into 3He. The reason is that the cores of these objects are supported against → gravitational collapse by electron → degeneracy pressure (at early spectral types) and → Coulomb pressure (at later spectral types). Brown dwarfs, as ever cooling objects, will have late M dwarf spectral types within a few Myrs of their formation and gradually evolve as L, T and Y dwarfs → brown dwarf cooling. As late-M and early-L dwarfs, they overlap in temperature with the cool end of the stellar → main sequence (→ M dwarf, → L dwarf, → T dwarf, → Y dwarf). In contrast to the OBAFGKM sequence, the M-L-T-Y sequence is an evolutionary one. These objects were first postulated by Kumar (1963, ApJ 137, 1121 & 1126) and Hayashi & Nakano (1963, Prog. Theor.Phys. 30, 460).
brown dwarf cooling
sardeš-e kutule-ye qahve-yi
Fr.: refroidissement de naine brune
The process whereby a → brown dwarf cools over time after the → deuterium burning phase, which lasts a few 107 years. The → effective temperature and luminosity decrease depending on the mass, age, and → metallicity. Even though massive brown dwarfs may start out with star-like luminosity (≥ 10-3→ solar luminosities), they progressively fade with age to the point where, after 0.5 Gyr all → substellar objects are less luminous than the dimmest, lowest mass stars. More explicitly, brown dwarfs may start as star-like objects hotter than 2200 K, with → M dwarf spectral types, and, as they get older, pass through the later and cooler L, T, and Y spectral types (→ L dwarf, → T dwarf, → Y dwarf).
brown dwarf desert
kavir-e kutulehâ-ye qahvei
Fr.: désert des naines brunes
The observational result indicating a deficit in the frequency of → brown dwarf companions to Sun-like stars, either relative to the frequency of less massive planetary companions or relative to the frequency of more massive stellar companions. However, this desert exists mainly for low-separation brown dwarfs detected using orbital velocity surveys. No brown dwarf desert is noticed at wide separations (J. E. Gizis et al. 2001, ApJ 551, L163).
DA white dwarf
sefid kutule-ye DA
Fr.: naine blanche DA
DB white dwarf
sefid kutule-ye DB
Fr.: naine blanche DB
A → white dwarf whose spectrum shows strong He I in the absence of hydrogen or metal lines.
DC white dwarf
sefid kutule-ye DC
Fr.: naine blanche DC
A → white dwarf showing a continuous spectrum with no readily apparent lines.
Fr.: naine dégénérée
Same as → white dwarf.
Fr.: dewar, vase dewar
Insulated bottle containing a cryogenic fluid. The electronic detectors operated at very low temperature are mounted inside a dewar.
Named after its inventor Sir James Dewar (1842-1923), Scottish chemist and physicist.
DO white dwarf
sefid kutule-ye DO
Fr.: naine blanche DO
A → white dwarf whose spectrum shows strong lines of singly ionized helium He II; He I or H may be present. As a DO star cools, the He II will recombine with free electrons to form He I, eventually changing the DO type into a DB white dwarf.
double white dwarf
sefid kutule-ye dotâyi
Fr.: naine blanche double
A → double-lined binary with two → white dwarf components. Short-period double white dwarfs can lose → orbital angular momentum by emitting → gravitational radiation and if the total mass of the binary exceeds the → Chandrasekhar limit, their eventual → merger might produce a → Type Ia supernova.
DQ white dwarf
sefid kutule-ye DQ
Fr.: naine blanche DQ
A → white dwarf whose spectrum shows carbon features of any kind.