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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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<< < -es -iv -ti 21- A r abe abs abs acc acc acc act act ada adi adu aff age alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg ari art ass ast ast ast atm ato att aur aut axi B r bac Bal Bar Bar Bay bec Ber Bet Bie bij bin bio bis bla bla blu blu bol Bor bou Bra bre bro Bug C-s cal Cam can car Car Cas cat cav cel cen cer Cha cha cha che cho cir cir cir cla clo clo clu coa coe coh col col col com com com com com com com com com con con con con con con con con con con con coo cor Cor cor cos cos cos Cou cou cra cre cro cru cub cur cyc Cyn dar dat day de- dec dec dec def def deg del den dep Des det deu dex die dif dif dil dip dir dis dis dis dis dis div dom Dor dou Dra duc dus dwa dyn e-t ear ecl eco eff Ein Ein ele ele ele ele ele elv emi emp ene enr epa epo equ equ Err Eta Eul eva evo exc exc exh exo exp exp ext ext Fab fai fan fau fel fer fic fil fin fir fla fli flu foc for for for fra fre fre fro fun fuz Gal gal gal Gar gau geg gen geo geo geo ger gla gly gra gra gra gra gra Gre gro GYR Had Hal hap Har HD hea hel hel hep Her hex hig Him hol hor hos hov Hub Hun hyd hyd hyd hyp IC ide ill Ima imp imp inc inc ind ine inf inf inf ini inp ins ins int int int int Int int int int inv ion Iri irr iso iso ite jel Jou JUp Kan Kep Kil kin Kra Lag Lam Lan Lar las law lea Leg Leo lev lig lim lin lin lin lit loc loc log Lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal mar mas mas mat max mea mec meg men mer met met Met mic mid Mil min Mir mix mod mod mol mon mor mov mul mur n-b nan nat nea neg Ner neu new New NGC noc nom non non nor nou nuc nuc num O-p obl obs obs oce Of? ohm omn opa Oph opt opt or orb ord Ori ort osc out ove ozo pal pan par par par par pat pec pen per per per per per Pfu pha pho pho pho phy pie pla Pla pla pla pla plu poi pol pol pol pol por pos pot pow pre pre pre pre pri pri pri pro pro pro pro Pro pro Prz pul pum Pyx qua qua qua qua R A rad rad rad rad rad rad Ram Ran rat rea rea rec rec red red ref ref reg rei rel rel rem rep res res res ret rev rhy rif Rin rob Rom rot rot rum S s Sak San sav sca Sch Sch scr sec sec SED sei sel sem seq sex Sha she sho sid sig sil sim sin siz sla Sma SNR Sof sol sol sol sol sou sou spa spe spe spe spe sph spi spo squ sta sta sta sta ste ste ste sto sto str str sub sub sub sum sup sup sup sup sur sus sym syn syz tan tea tem ten ter the the the the thi thr tid til tip tom tor tou tra tra tra tra Tri tri tru tsu tur two Typ ult umb unc uni uni unk upp urg uvb val var Veg vel ver vib vio vir vis Voi vow wan wat wav WC wea wel whi Wil wir WNh wor X-r Yer Z s zer [C > >>

Number of Results: 12942 Search : far
bolometric luminosity
  تابندگی ِ تفسنجی، ~ تفسنجیک   
tâbandegi-ye tafsanji, ~ tafsanjik

Fr.: luminosité bolométrique   

The total rate of energy output of an object integrated over all wavelengths.

bolometric; → luminosity.

bolometric magnitude
  برز ِ تفسنجی، ~ تفسنجیک   
borz-e tafsanji, ~ tafsanjik

Fr.: magnitude bolométrique   

The magnitude of an astronomical object for the entire range of its electromagnetic spectrum.

bolometric; → magnitude.

Boltzmann constant
  پایای ِ بولتسمن   
pâyâ-ye Boltzmann

Fr.: constante de Boltzmann   

Boltzmann's constant.

Boltzmann's constant.

Boltzmann factor
  کروند ِ بولتسمن   
karvand-e Boltzmannn

Fr.: facteur de Boltzmann   

The factor e-E/kT involved in the probability for atoms having an excitation energy E and temperature T, where k is Boltzmann's constant.

Boltzmann's constant; → factor.

Boltzmann's constant
  پایای ِ بولتسمن   
pâyâ-ye Boltzmann

Fr.: constante de Boltzmann   

The physical constant, noted by k, relating the mean → kinetic energy of → molecules in an → ideal gas to their → absolute temperature. It is given by the ratio of the → gas constant to → Avogadro's number. Its value is about 1.380 x 10-16erg K-1.

Named after the Austrian physicist Ludwig Boltzmann (1844-1906), who made important contributions to the theory of statistical mechanics; → constant.

Boltzmann's entropy formula
  دیسول ِ درگاشت ِ بولتسمن   
disul-e dargâšt-e Boltzmann

Fr.: formule d'entropie de Boltzmann   

In → statistical thermodynamics, a probability equation relating the → entropy S of an → ideal gas to the quantity Ω, which is the number of → microstates corresponding to a given → macrostate: S = k. ln Ω. Same as → Boltzmann's relation.

Boltzmann's constant; → entropy; → formula.

Boltzmann's equation
  هموگش ِ بولتسمن   
hamugeš-e Boltzmann

Fr.: équation de Boltzmann   

1) An equation that expresses the relative number (per unit volume) of → excited atoms in different states as a function of the temperature for a gas in → thermal equilibrium: Nu/Nl = (gu/gl) exp (-ΔE/kTex), where Nu and Nl are the upper level and lower level populations respectively, gu and gl the → statistical weights, ΔE = hν the energy difference between the states, k is → Boltzmann's constant, and h  → Planck's constant.

Boltzmann's constant; → equation.

Boltzmann's relation
  باز‌آنش ِ بولتسمن   
bâzâneš-e Boltzmann

Fr.: relation de Boltzmann   

A relation between the → entropy of a given → state of a → thermodynamic system and the → probability of the state: S = k . ln Ω where S is the entropy of the system, k is → Boltzmann's constant, and Ω the thermodynamic probability of the state. Boltzmann's relation connects → statistical mechanics and → thermodynamics. Ω is the number of possible → microstates of the system, and it represents the → randomness of the system. The relation also describes the statistical meaning of the → second law of thermodynamics. This expression has been carved above Boltzmann's name on his tombstone in Zentralfreihof in Vienna. Same as → Boltzmann's entropy formula.

Boltzmann's constant; → relation.

bond
  بند   
band (#)

Fr.: lien   

The → attractive force that holds together neighboring → atoms in → molecules.

Bond, variant of band, from M.E. bende, O.E. bend, from O.Fr. bande, bende, PIE *bendh- "to bind" (cf. Goth bandi "that which binds;" Av./O.Pers. band- "to bind, fetter," banda- "band, tie" (see below); Skt. bandh- "to bind, tie, fasten," bandhah "a tying, bandage").

Band "band, tie," from Mid.Pers., O.Pers./Av. band- "to bind," banda- "band, tie," also present stem of bastan "to bind, shut," → shutter.

Bond albedo
  سپیدای ِ باند   
sepidâ-ye Bond

Fr.: albedo de Bond   

The fraction of the total amount of electromagnetic radiation falling upon a non-luminous spherical body that is reflected in all directions by that body. The bond albedo takes into account all wavelengths at all → phase angles. Compare with → geometric albedo.

Named after the American astronomer George Phillips Bond (1825-1865), who proposed it; → albedo.

Bondi-Hoyle accretion
  فربال ِ بوندی-هویل   
farbâl-e Bondi-Hoyle

Fr.: accrétion de Bondi-Hoyle   

The → accretion of mass by a star (assumed as point particle) moving at a steady speed through an infinite, uniform gas cloud. It is directly proportional to the star mass (M) and the medium density (ρ) and inversely proportional to the relative star/gas velocity (v). In its classical expression: 4πρ(G M)2 / v3, where G is the → gravitational constant. See Bondi & Hoyle (1944, MNRAS 104, 273) and Bondi (1952, MNRAS 112, 195). For a recent treatment of accretion in a turbulent medium see Krumholtz et al. 2006 (ApJ 638, 369).

Named after Hermann Bondi (1919-2005), an Anglo-Austrian mathematician and cosmologist and Fred Hoyle (1915-2001), British mathematician and astronomer best known as the foremost proponent and defender of the steady-state theory of the universe; → accretion.

Bondi-Hoyle accretion radius
  شعاع ِ فربال ِ بوندی-هویل   
šo'â'-e farbâl-e Bondi-Hoyle

Fr.: rayon de l'accrétion de Bondi-Hoyle   

In the → Bondi-Hoyle accretion process, the radius where the gravitational energy owing to star is larger than the kinetic energy and, therefore, at which material is bound to star. The Bondi-Hoyle accretion radius is given by RBH = 2 GM / (v2 + cs2) where G is the gravitational constant, M is the stellar mass, v the gas/star relative velocity, and cs is the sound speed.

Bondi-Hoyle accretion; → radius.

Bonner Durchmusterung (BD)
     
Bonner Durchmusterung

Fr.: Bonner Durchmusterung   

A catalog of 324,188 stars in the → declination zones +89 to -01 degrees. The goal of the survey was to obtain a → position and estimated → visual magnitude for every star visible with the 78 mm → refracting telescope at Bonn. Actual → magnitude estimates were made and reported to 0.1 mag for all stars down to 9.5 mag. Positions are given to the nearest 0.1 sec in → right ascension and 0.1 arcmin in declination. The survey was carried out by Friedrich W. Argelander (1799-1875) and his assistants in the years 1852-1861.

The Ger. name means Bonn Survey.

Bonnor-Ebert mass
  جرم ِ بونور-ابرت   
jerm-e Bonnor-Ebert

Fr.: masse de Bonnor-Ebert   

The largest gravitationally stable mass of the → Bonnor-Ebert sphere.

After W.B. Bonnor (1956) and R. Ebert (1955); → mass.

Bonnor-Ebert sphere
  سپهر ِ بونور-ابرت، کره‌ی ِ ~   
epehr-e Bonnor-Ebert, kore-ye ~

Fr.: sphère de Bonnor-Ebert   

A sphere of interstellar gas at uniform temperature in equilibrium under its own gravitation and an external pressure. The pressure of a hotter surrounding medium causes the sphere to collapse. → Bonnor-Ebert mass.

Bonnor-Ebert mass; → sphere.

book
  کتاب، نامه، نسک   
ketâb (#), nâmé (#), nask (#)

Fr.: livre   

A bound set of printed or manuscript pages.

M.E., from O.E. boc "book, written document;" cf. Ger. Buch "book;" Du. boek; O.N. bôk; Gothic boka.

Ketâb, loanword from Ar.
Nâmé "book, letter;" Mid.Pers. nâmag "book, letter, inscription;" O.Pers./Av. nāman- "name;" cf. Skt. nama-; Gk. onoma, onuma; L. nomen; PIE *nomen-.
Nask; Mid.Pers. nask "one of the book comprising Avesta;" Av. naska-, literally "bundle, bunch," naskô.frasa- "one who devotes himself to the study of nasks;" cf. Skt. nah- "to tie, bind," nahyati "he ties, binds;" L. nectere "to tie, bind," nodus "node;" O.Ir. nasc "a tie, bond, ring," nascim "I bind."

Boolean
  بولی   
Booli (#)

Fr.: de Boole   

A → variable or → function which takes the value → true or → false. → Boolean algebra.

After the English mathematician George Boole (1815-1864), the founder of mathematical, or symbolic, logic.

Boolean algebra
  جبر ِ بولی   
jabr-e Booli (#)

Fr.: algèbre de Boole   

Any of a number of possible systems of mathematics that deals with → binary digits instead of numbers. In Boolean algebra, a binary value of 1 is interpreted to mean → true and a binary value of 0 means → false. Boolean algebra can equivalently be thought of as a particular type of mathematics that deals with → truth values instead of numbers.

Boolean; → algebra. The term Boolean algebra was first suggested by Sheffer in 1913.

Boomerang Nebula
  میغ ِ بومرانگ   
miq-e bumerâng

Fr.: nébuleuse du Boomerang   

A → nebula displaying two nearly symmetric lobes of matter that are being ejected from a central star at a speed of about 600,000 km per hour (each lobe nearly one light-year in length). The Boomerang Nebula resides 5,000 → light-years from Earth in the direction of the Southern constellation → Centaurus.

Boomerang, adapted from wo-mur-rang, boo-mer-rit, in the language of Australian aborigines; → nebula.

Bootes
  گاوران، گایار   
Gâvrân, Gâyâr

Fr.: Bouvier   

The Herdsman, the Ox Driver. A constellation in the northern hemisphere, at right ascension about 14h 30m, north declination about 30°. Its brightest star is → Arcturus. Abbreviation: Boo; genitive form: Boötis.

L. Boötes, from Gk. bootes "plowman," literally "ox-driver," from bootein "to plow," from bous "ox," from PIE *gwou- "ox, bull, cow;" compare with Av. gao-, gâuš "bull, cow, ox," Mod.Pers. gâv, Skt. gaus, Armenian kov, O.E. cu.

Gâvrân "ox-driver," from gâv "ox, cow" + rân "driver," from rândan "to drive."
Gâyâr, from Lori "bull driver, plower, plow man" (Tabari goyâr), from "bull, cow," variant of gâv, explained above, + -âr, either "driver", Av. ar- "to set in motion" (Skt. ir-, IER *er-), or IER *are- "to plow" (L. arare, Gk. aroun, O.C.S. orja, Lith. ariu, Goth. arjan, O.E. erian, Tokharian AB âre). Compare also with Gilaki urân " to plow," Qâeni ordu "plow".

<< < -es -iv -ti 21- A r abe abs abs acc acc acc act act ada adi adu aff age alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg ari art ass ast ast ast atm ato att aur aut axi B r bac Bal Bar Bar Bay bec Ber Bet Bie bij bin bio bis bla bla blu blu bol Bor bou Bra bre bro Bug C-s cal Cam can car Car Cas cat cav cel cen cer Cha cha cha che cho cir cir cir cla clo clo clu coa coe coh col col col com com com com com com com com com con con con con con con con con con con con coo cor Cor cor cos cos cos Cou cou cra cre cro cru cub cur cyc Cyn dar dat day de- dec dec dec def def deg del den dep Des det deu dex die dif dif dil dip dir dis dis dis dis dis div dom Dor dou Dra duc dus dwa dyn e-t ear ecl eco eff Ein Ein ele ele ele ele ele elv emi emp ene enr epa epo equ equ Err Eta Eul eva evo exc exc exh exo exp exp ext ext Fab fai fan fau fel fer fic fil fin fir fla fli flu foc for for for fra fre fre fro fun fuz Gal gal gal Gar gau geg gen geo geo geo ger gla gly gra gra gra gra gra Gre gro GYR Had Hal hap Har HD hea hel hel hep Her hex hig Him hol hor hos hov Hub Hun hyd hyd hyd hyp IC ide ill Ima imp imp inc inc ind ine inf inf inf ini inp ins ins int int int int Int int int int inv ion Iri irr iso iso ite jel Jou JUp Kan Kep Kil kin Kra Lag Lam Lan Lar las law lea Leg Leo lev lig lim lin lin lin lit loc loc log Lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal mar mas mas mat max mea mec meg men mer met met Met mic mid Mil min Mir mix mod mod mol mon mor mov mul mur n-b nan nat nea neg Ner neu new New NGC noc nom non non nor nou nuc nuc num O-p obl obs obs oce Of? ohm omn opa Oph opt opt or orb ord Ori ort osc out ove ozo pal pan par par par par pat pec pen per per per per per Pfu pha pho pho pho phy pie pla Pla pla pla pla plu poi pol pol pol pol por pos pot pow pre pre pre pre pri pri pri pro pro pro pro Pro pro Prz pul pum Pyx qua qua qua qua R A rad rad rad rad rad rad Ram Ran rat rea rea rec rec red red ref ref reg rei rel rel rem rep res res res ret rev rhy rif Rin rob Rom rot rot rum S s Sak San sav sca Sch Sch scr sec sec SED sei sel sem seq sex Sha she sho sid sig sil sim sin siz sla Sma SNR Sof sol sol sol sol sou sou spa spe spe spe spe sph spi spo squ sta sta sta sta ste ste ste sto sto str str sub sub sub sum sup sup sup sup sur sus sym syn syz tan tea tem ten ter the the the the thi thr tid til tip tom tor tou tra tra tra tra Tri tri tru tsu tur two Typ ult umb unc uni uni unk upp urg uvb val var Veg vel ver vib vio vir vis Voi vow wan wat wav WC wea wel whi Wil wir WNh wor X-r Yer Z s zer [C > >>