An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Optics: A strip or annulus of material, such as glass or film, whose density increases progressively from one end to the other. The function of the wedge is to weaken the light beam in an optical system.

Verbal adj. from → absorb; → wedge.

A linear combination of vectors in which all the vector coefficients add up to one.

→ affine; → combination.

A binary star in which the presence of an unresolved companion is revealed by small oscillations in the movement of the visible component caused by the gravitational influence of the unseen component.

→ astrometry; → binary.

A crystal device made of two → quartz  → prisms with equal acute angles assembled in a rhombus that is used in analyzing → polarized light. The wedge-shaped prisms are placed against each other and can be displaced along their plane of contact by a → micrometer. Thus they form a parallel plate of variable thickness allowing the optical retardation to be adjusted.

Jacques Babinet (1794-1872), French physicist; → compensator.

One of several points on the sky where the degree of → linear polarization is zero in skylight. See also → neutral point; → Arago point, → Brewster point.

→ Babinet compensator; → point.

The → diffraction pattern for an → aperture is the same as the diffraction pattern for its → complementary aperture.

→ Babinet compensator; → principle.

1a) General:A box or enclosed space for storing grain, coal, or the like.
1b) Electronics: In a → CCD detector, a square or rectangular group of adjacent → pixels used collectively to transport the → electron charges.
1c) In a statistical → histogram, the range of → distribution → intervals. The bin widths (or the number of bins) affect a histogram.
2) To place in a → bin; to create → binning.

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.

→ binary; → -ity.

General: Characterized by or consisting of two parts or components.
Math.: Of or relating to a system of numeration having 2 as its base.
Astro.: Physically associated pair of astronomical objects.

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."
Dodoyi "two-by-two," from do, → two.

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.

→ binary; → arithmetic.

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; → asteroid.

A → binary system consisting of two → black holes in close orbit around each other. Same as → black hole binary.

→ binary; → black; → hole.

Either of the digits 0 or 1, used in the → binary number system.

→ binary, → digit.

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).

→ binary; → frequency.

A pair of galaxies in orbit around each other.

→ binary; → galaxy.

Kahkašân, → galaxy; dorin→ binary.

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.

→ binary; → number; → system.

A mathematical operation that combines two numbers, quantities, sets, etc., to give a third. For example, multiplication of two numbers is a binary operation.
A binary operation * on a set S is → commutative if a * b = b * a for all a, b∈ S.
A binary operation * on a set S is → associative if (a * b) * c = a * (b * c) for all a, b, c∈ S.

→ binary; → operation.

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.

→ binary; → pulsar.

Two stars gravitationally bound to each other, so that they revolve around their common center of gravity. → double star; → spectroscopic binary.

→ binary; → star.

Setâré, → star; dorin, → binary.

A → dual supermassive black hole whose components are separated by a few parsecs.

→ binary; → supermassive; → black; → hole.