An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < B r bac Bal Bar bar bea bel Bes bia Big bin bio bir bla bla blu blu bol Bor bou Bra bre bro bul > >>

Number of Results: 476
Borda circle
  دایره‌ی ِ بُردا   
dâyere-ye Borda

Fr.: cercle de Borda   

An instrument which was an improved form of the → reflecting circle, used for measuring angular distances. In Borda's version the arm carrying the telescope was extended right across the circle. The telescope and a clamp and tangent screw were at one end, and the half-silvered horizon glass at the far end from the eye. In practice, with the index arm clamped, the observer first aims directly at the right hand object and by reflection on the left, moving the telescope arm until this is achieved. He then frees the index arm, sights directly on the left hand object with the telescope arm clamped, and moves the index arm until the two coincide again. The difference in the readings of the index arm is twice the angle required, so that the final sum reading must be divided by twice the number of double operations. Borda's instrument greatly contributed to the French success in measuring the length of the meridional arc of the Earth's surface between Dunkirk and Barcelona (1792-1798). The operation carried out by Jean Baptiste Delambre (1749-1822) and Pierre Méchain (1744-1804) was essential for establishing the meter as the length unit.

After the French physicist and naval officer Jean-Charles de Borda (1733-1799), who made several contributions to hydrodynamics and nautical astronomy. Borda was also one of the most important metrological pioneers; → circle.

zâdé (#)

Fr.: né   

Brought forth by → birth. Past participle of bear. → born-again AGB star.

M.E., from O.E. boren, p.p. of beran "to bear, bring, wear", from P.Gmc. *beranan (O.H.G. beran, Goth. bairan "to carry"), from PIE root *bher- "to bear; to carry" (cf. Av./O.Pers. bar- "to bear, carry," bareθre "to bear (infinitive)," bareθri "a female that bears (children), a mother," Mod.Pers. bordan "to carry," bâr "charge, load", bârdâr "pregnant," Skt. bharati "he carries," Gk. pherein).

Zâdé "born," p.p. of zâdan "give birth" (Av. zan- "to bear, give birth to a child, be born," infinitive zizâite, zâta- "born," cf. Skt. janati "begets, bears," Gk. gignesthai "to become, happen," L. gignere "to beget," gnasci "to be born," PIE base *gen- "to give birth, beget").

born-again AGB star
  ستاره‌یِ AGBیِ باز‌زاده   
setâre-ye AGB-ye bâzzâdé

Fr.: étoile AGB recyclée   

A → post-AGB star that undergoes a last → thermal pulse when it is already on the → white dwarf  → cooling track. The thermal pulse will expand the hot central star, whereby hydrogen will be ingested into the → helium burning shell. This will temporarily return the star to the → AGB phase it has previously left.

born; → again; → asymptotic giant branch; → star.

born-again planetary nebula
  میغ ِ سیاره‌ای ِ باز‌زاد   
miq-e sayâreyi-ye bâzzâd

Fr.: nébuleuse planétaire recyclée   

A → planetary nebula which is thought to have experienced a → very late thermal pulse (VLTP) when the central star (→ CSPN) was on the → white dwarf cooling track. The VLTP event occurs when the thermonuclear → hydrogen shell burning has built up a → shell of helium with the critical mass to ignite its → fusion into carbon and oxygen (→ helium shell burning). Since the → white dwarf envelope is shallow, the increase of pressure from this last helium shell flash leads to the ejection of newly processed material inside the old planetary nebula, leaving the stellar core intact. As the stellar envelope expands, its → effective temperature decreases and the star goes back to the → asymptotic giant branch (AGB) region in the → H-R diagram. The subsequent stellar evolution is fast and will return the star back to the → Post-AGB track in the H-R diagram: the envelope of the star contracts, its effective temperature and ionizing photon flux increase, and a new fast stellar wind develops (see, e.g. J. A. Toalá et al. 2015, ApJ 799, 67).

born; → again; → planetary; → nebula.

bor (#)

Fr.: bore   

A soft, brown, nonmetallic chemical element; symbol B. → Atomic number 5; → atomic weight 10.81; → melting point about 2,300°C; → specific gravity 2.3 at 25°C; → valence +3. Boron occurs as borax and boric acid. It is used for hardening steel and for producing enamels and glasses. Since it absorbs slow neutrons, it is used in steel alloys for making control rods in nuclear reactors. Boron was separated in 1808 by Joseph Louis Gay Lussac (1778-1850) and Louis Jacques Thénard (1777-1857) and independently by Sir Humphry Davy (1778-1829).

From bor(ax), from M.Fr. boras, from M.L. borax, from Ar. buraq, from Pers. burah "borax, nitre, used in soldering gold" + (car)bon.

Bor, loan from Fr., as above.

Bose-Einstein condensate (BEC)
  چگالاک ِ بوز-اینشتین   
cagâlâk-e Bose-Einstein

Fr.: condensat de Bose-Einstein   

A state of matter in which a group of atoms or subatomic particles, cooled to within → absolute zero, coalesce into a single quantum mechanical entity that can be described by a → wave function. When a group of atoms are cooled down to very near absolute zero, the atoms hardly move relative to each other, because they have almost no free energy to do so. Hence the atoms clump together and enter the same → ground energy states. They become identical and the whole group starts behaving as though it were a single atom. A Bose-Einstein condensate results from a → quantum transition phase called the → Bose-Einstein condensation. This form of matter was predicted in 1924 by Albert Einstein on the basis of the quantum formulations of the Indian physicist Satyendra Nath Bose.
Bose-Einstein condensate was created for the first time in the laboratory in 1995. The three physicist who succeeded in producing BEC, Eric A. Cornell, Wolfgang Ketterle, and Carl E. Wieman, were awarded the 2001 Nobel Prize in Physics. Cornell and Wieman managed to do that with about 2,000 → rubidium atoms cooled down to 20 nano K, while Ketterle used more than 100,000 → sodium atoms.

boson; → Einstein; → condensate.

Bose-Einstein condensation (BEC)
  چگالش ِ بوز-اینشتین   
cagâleš-e Bose-Einstein

Fr.: condensation de Bose-Einstein   

A → quantum phase transition during which the → bosons constituting a sufficiently cooled boson gas are all clustered in the → ground energy state. The phase transition results in a → Bose-Einstein condensate. This phenomenon occurs when the temperature becomes smaller than a critical value given by: Tc = (2πħ2 / km)(n / 2.612)2/3, where m is mass of each boson, ħ is the → reduced Planck's constant, k is → Boltzmann's constant, and n is the particle number density. When T  ≤  Tc, the → de Broglie wavelength of bosons becomes comparable to the distance between bosons.

boson; → Einstein; → condensation.

Bose-Einstein distribution
  واباژش ِ بوز-اینشتین   
vâbâžeš-e Bose-Einstein

Fr.: distribution de Bose-Einstein   

For a → population of independent → bosons, a function that specifies the number of particles in each of the allowed → energy states.

boson; → Einstein; → distribution.

Bose-Einstein statistics
  آمار ِ بوز-اینشتین   
âmâr-e Bose-Einstein (#)

Fr.: statistique de Bose-Einstein   

Same as → Bose-Einstein distribution.

boson; → Einstein; → statistics.

boson (#)

Fr.: boson   

Any of a class of particles (such as the → photon, → pion, or → alpha particle) that have zero or integral → spin and do not obey the → Pauli exclusion principle. The energy distribution of bosons is described by → Bose-Einstein statistics. See also: → gauge boson, → Higgs boson, → W boson, → Z boson, → intermediate boson.

Boson, in honor of the Indian-American physicist Satyendra Nath Bose (1894-1974).

giyâhšenâsi (#)

Fr.: botanique   

The branch of → biology that deals with → plants.

From botanic, from Fr. botanique, M.L. botanicus, from Gk. botanikos "of herbs," from botane "herb, grass, pasture."

Giyâhšenâsi, from giyâh, → plant, + šenâsi, → -logy.

Botein (δ Ari)
Boteyn (#)

Fr.: Botein   

A dim, red star in the constellation → Aries; a → giant of → spectral type K2 III at a distance of 168 light-years.

Botein, from Ar. Al-Butain "the little belly."

Boteyn, from Ar. Al-Butain.

botri (#)

Fr.: bouteille   

A portable vessel for liquids, typically cylindrical and often of glass or plastic with a narrow neck that can be closed. → magnetic bottle, → Leyden jar.

From O.Fr. bo(u)teille, from L.L. butticula diminutive of L. buttis "a cask."

Botri, loan from Fr. bouteille or E. bottle, as above.

  ته، پایین   
tah (#), pâyin (#)

Fr.: bas, fond   

1) The lowest or deepest part of anything, as distinguished from the → top. The under or lower side; underside. → bottom-up structure formation.
2) → bottom quark.

M.E. botme; O.E. botm, bodan "ground, soil, lowest part" (cf. O.Fris. boden "soil," O.N. botn, O.H.G. bodam, Ger. Boden "ground, earth, soil"), akin to Pers. bon "basis; root; foundation; bottom;" Mid.Pers. bun "root; foundation; beginning;" Av. būna- "base, depth" (Skt. bundha-, budhná- "base, bottom," Pali bunda- "root of tree;" Gk. pythmen "foundation;" L. fundus "bottom, piece of land, farm," O.Ir. bond "sole of the foot").

Tah "bottom; end" (Mid.Pers. tah "bottom." The origin of this term is not clear. It may be related to PIE *tenegos "water bottom;" cf. Gk. tenagos "bottom, swamp," Latvian tigas, from *tingas, from *tenegos "depth").
Pâyin "bottom, below; at the foot of," from pâ(y) "foot; step" (Mid.Pers. pâd, pây; Av. pad- "foot;" cf. Skt. pat; Gk. pos, genitive podos; L. pes, genitive pedis (Fr. pied); P.Gmc. *fot (E. foot; Ger. Fuss); PIE *pod-/*ped-); + -in a relation suffix.

bottom-up structure formation
  دیسش ِ ساختار از پایین به بالا   
diseš-e sâxtâr az pâyin bé bâlâ

Fr.: formation des structures du bas vers le haut   

A → structure formation scenario in which small galaxies form first, and larger structures are then formed in due course. Contrary to → top-down structure formation.

bottom; → up; → structure; → formation; → galaxy.

  ۱) بندیده؛ ۲) کران   
1) bandidé; 2) karân

Fr.: lié; lien   

1) (adj.) Tied, confined by bonds. → bound cluster, → bound charge, → bound system.
2) (n) a boundary; a limit.

1) p.p. of → bind. 2) → boundary.

bound charge
  بارِ بندیده   
bâr-e bandidé

Fr.: charge liée   

Any electric charge which is bound to an atom or molecule, in contrast to free charge, such as metallic conduction electrons, which is not. Also known as → polarization charge.

bound; → charge.

bound cluster
  خوشه‌ی ِ بندیده   
xuše-ye bandidé

Fr.: amas lié   

A cluster of astronomical objects, such as stars or galaxies, held together by their mutual gravitational attraction. → bound system.

Bound, p.p. of → bind; → cluster.

Xušé, → cluster; bandidé p.p. of bandidan, → bind.

bound occurrence
  رخداد ِ بندیده   
roxdâd-e bandidé

Fr.: occurrence liée   

Any → occurrence of a → variable  x in an x-bound part of a → wff.

bound; → occurrence.

bound orbit
  مدار ِ بندیده   
madâr-e bandidé

Fr.: orbite liée   

The orbit described by an object around a central gravitational force in a system whose total energy is negative. An elliptical orbit.

Bound, p.p. of → bind; → orbit.

Madâr, → orbit; bandidé, p.p. of bandidan, → bind.

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