bimodal star formation
diseš-e domod-e setâregân
Fr.: formation bimodale d'étoile
A concept of → star formation in which → high-mass stars and → low-mass stars form in different physical conditions involving different → molecular clouds. Following the pioneering suggestion of Herbig (1962), successive investigations have generally supported the idea that star formation proceeds bimodally with respect to stellar mass. The star formation rate appears to differ both spatially and temporally for low mass and → massive stars. This is of considerable importance for galactic evolution, since the low-mass stars lock up mass and are long-lived, low luminosity survivors to the present epoch, whereas massive stars are short-lived, recycle and enrich interstellar gas, and leave dark remnants while producing a high luminosity per unit of mass (Silk, J., 1988, in Galactic and Extragalactic Star Formation, p. 503, eds. R. E. Pudritz and M. Fich).
The quality or state of being → bimodal.
1) bâvin; 2) bâvinidan
Fr.: 1) bin; 2) binner
1a) General:A box or enclosed space for storing grain, coal, or
M.E. binne, O.E. binn(e) "manger, crib," perhaps from O.Celt. *benna, akin to Welsh benn "a cart, especially one with a woven wicker body." The same Celtic word seems to be preserved in It. benna "dung cart," Fr. benne "a sort of box for transporting materials, especially in mines," Du. benne "large basket," from L.L. benna.
Bâvin "a basket, more precisely a small basket which contains the cotton to be spun;" bâvinidan infinitive from bâvin.
The quality or condition of being binary.
dorin, dodoyi (#)
General: Characterized by or consisting of two parts or
Binary, from L.L. binarius, from bini "two-by-two," from bis "twice, two times;" cf. Av. biš- "twice," bi- "two," Mod.Pers. do "two," PIE *dwo- "two."
Dorin, from Mid.Pers. dorin "double, pair,"
from do (Av. dva-, Skt. dvi-, Gk. duo,
L. duo, E. two, Der. zwei, Fr. deux)
"two" + rin "time, turn."
hesâb-e dorin, ~ dodoi (#)
Fr.: arithmétique binaire
A system of calculation in which the only numerals used are 0 and 1. All the real numbers are represented in terms of powers of 2.
Fr.: astéroïde binaire
A member of a population of double objects in the main → Asteroid Belt or the → Kuiper Belt which are gravitationally bound together. So far about 200 such binary systems have been identified, while their number is increasing. 243 Ida was the first binary asteroid to be discovered during the Galileo spacecraft flyby in 1993. Other examples are → Antiope and Kalliope in the main belt and QG298 in the Kuiper Belt. The importance of these objects resides in the fact that systems with well measured orbital parameters allow the total mass to be estimated. If the sizes of the components are known then their densities can be accurately calculated. Density is an important parameter since it yields information about composition and internal structure.
binary black hole
siyah câl-e dorin
Fr.: trou noir binaire
binary digit (bit)
raqam-e dorin, ~ dodoi, bit
Fr.: chiffre binaire
Either of the digits 0 or 1, used in the → binary number system.
Fr.: fréquence des binaires
The fraction of stars that have at least one → companion. It is at least 50%. The binary fraction appears to increase with increasing → primary star mass, at least among the more massive stars: the → O stars and → B stars have a companion frequency of at least 70%, while for the → G stars the binary frequency is around 50% and the → M stars may have an even lower binary frequency of around 30-40%. Brown dwarfs are rare as companions to lower-main-sequence stars, although brown-dwarf binaries appear not to be rare. An increase in binary frequency with mass would be expected if most stars form in → multiple systems that disintegrate, since the more massive stars would then preferentially remain in binaries while the less massive ones would preferentially be ejected as single stars (see Richard B. Larson, 2001, in IAU Symposium 200, p. 93 and references therein).
Fr.: galaxie binaire
A pair of galaxies in orbit around each other.
→ binary; → galaxy.
binary number system
râžmân-e adadhâ-ye dirini
Fr.: système des nombres binaires
A → numeral system that has 2 as its base and uses only two digits, 0 and 1. The positional value of each digit in a binary number is twice the place value of the digit of its right side. Each binary digit is known as a bit. The decimal numbers from 0 to 10 are thus in binary 0, 1, 10, 11, 100, 101, 110, 111, 1000, 1001, and 1010. And, for example, the binary number 111012 represents the decimal number (1 × 24) + (1 × 23) + (1 × 22) + (0 × 21) + (1 × 20), or 29. In electronics, binary numbers are the flow of information in the form of zeros and ones used by computers. Computers use it to manipulate and store all of their data including numbers, words, videos, graphics, and music.
Fr.: opération binaire
A mathematical operation that combines two numbers, quantities, sets, etc.,
to give a third. For example, multiplication of two numbers is a binary operation.
pulsâr-e dorin, tapâr-e ~
Fr.: pulsar binaire
A pulsar in a → binary system, the companion of which often being a → neutron star or a → white dwarf. The only known binary system with two pulsars components is the → double pulsar. As of 2010 about 70 binary pulsars have been identified. They are ideal laboratories for testing and studying the effects predicted by → general relativity, such as → spin precession, → Shapiro time delay, and → gravitational waves. The prototype, called PSR 1913+16, was discovered in 1974 by Russell A. Hulse and Joseph H. Taylor, Jr., who received the Nobel Prize for Physics in 1993. → Hulse-Taylor pulsar.
Fr.: étoile binaire
→ binary; → star.
binary supermassive black hole
siyah-câl-e abar-porjerm-e dorin
Fr.: trou noir supermassif double
A → dual supermassive black hole whose components are separated by a few parsecs.
Fr.: système binaire
Two astronomical objects revolving around their common center of mass.
→ binary; → system.
Fr.: arbre binaire
To tie, to fasten, to cause ti stick together.
O.E. bindan "to tie up with bonds," PIE base *bhendh- "to bind;" cf. Av./O.Pers. band- "to bind, fetter," banda- "band, tie," Skt. bandh- "to bind, tie, fasten," bandhah "a tying, bandage."
Bandidan "to bind, confine" [Mo'in, Dehxodâ], from band "band, tie" + -idan infinitive suffix; cognate with E. bind, as explained above.
kâruž-e bandeš, ~ hamgiri
Fr.: énergie de liaison
1) Of a gravitational system, the difference
in energies between the hypothetical state where all bodies of
the system are infinitely separated from each other and the actual bound state.