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 cri cro cub cur cyc cyl dar dat daw de- Deb dec dec dee def deg del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis div dog Dop dou dra dua dus dwa dyn e-m ear ecl eco eff ein Ein elb ele ele ele ele Els emi emp ene enr env epi equ equ Eri est Euc eva evo exc exc exh exo exp exp ext ext f-n Fah fam fau fee Fer fib fil fin fir fix fle flu foc for for for fra fre fre fri fun fuz gal gal gal Gan gau GCN gen geo geo geo geo Gl glo gra gra gra gra gra gre gro GW1 hab hal han HAR haz hea hel hel Hen Her heu Hig Hil hol hop hor hou Hub Hum Hyd hyd hyd hyp hys ide ign ima imp imp inc inc ind ine inf inf inf inh INP ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jos Jun K2 Kep key kin Kol lag lam Lan lar las lav lea leg len lev lig lim lin lin lin lis lob loc log lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal mar mas mas mat max mea mea mee Men mer met met met mic mid Mil min Mir mix mod mod mol mon Mor mou mul muo mys nan nat nav nec Nep neu New New NGC nob nom non non nor not nuc nuc num Nyq obj obs obs oce oen OH omn opa ope opt opt opt orb ord Ori ort osc out ove oxy pal pan par Par par par pas pea Pen per per per per per pet pha pho pho pho phy pie Pit Pla pla pla pla ple Poi pol pol pol pol pop pos pos pow pre pre pre Pre pri pri pri pro pro pro pro pro pro Pro pub pul pyr qua qua qua qua Qui rad rad rad rad rad rad ram ran rat rea rec rec rec red ref ref reg reg rel rel rem rep res res res ret rev rho Rie rim riv rol Ros rot rul S a Sah san Sat sca Sch Sch scr sec sec sec sei sel sem sep set sha she sho sid sig sil sim sin sit sky slu sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spl spr sta sta sta sta sta ste ste sti sto str str sub sub sub sug sun sup sup sup sup sur syl syn sys tal Tay tel ten ter tex the the the thi tho thu tid tim tod top tot tra tra tra tra tri tri tro tru tur twi Typ UFO ult unc uni uni uni upg ura uti val var vec vel ver ver vig vir vis voc von wak Was wav wax wea wei whi Wie win WN6 wom X-r yel you zer zod > >>

Number of Results: 12948 Search : far
yellow
  زرد   
zard (#)

Fr.: jaune   

The primary color between green and orange in the visible spectrum; an effect of light with a wavelength between 5700 and 5900 Å. → yellow giant; → yellow supergiant.

M.E. yelou; O.E. geolo, geolu; P.Gmc. *gelwaz (cf. O.S., O.H.G. gelo, M.Du. ghele, Du. geel, Ger. gelb, Swed. gul "yellow"); cognate with Pers. zar "yellow," as below.

Zard "yellow," related to zarr "gold;" Mid.Pers. zard "yellow," zarr "gold;" O.Pers. daraniya- "gold;" Av. zaray-, zairi- "yellow, green," zaranya-, zarənu- "gold;" cf. Skt. hari- "yellow, green," hiranya- "gold;" Gk. chloros "light green," chloe "green shoot;" L. helvus "yellowish, bay;" Rus. zeltyj "yellow;" P.Gmc. *gelwaz, as above.

yellow giant
  غول ِ زرد، غولپیکر ِ ~   
qul-e zard (#), qulpeykar-e ~ (#)

Fr.: géante jaune   

A star that appears in the upper-middle part of the → H-R diagram, to the left of the → red giants. Yellow giants are low-mass evolved stars that are burning their helium, on their path to the → planetary nebula stage. Most yellow giants behave as variable stars, usually because their outer layers pulsate. Periods of these pulsations are usually days or weeks. The Sun after leaving the red giant stage will become a pulsating yellow giant for some 100 million years.

yellow; → giant.

yellow hypergiant (YHG)
  هیپرغول ِ زرد   
hiperqul-e zard

Fr.: hypergéante jaune   

An evolved, → very massive star of spectral type F or G with a very high luminosity (~105 times solar) lying near the empirical upper luminosity boundary in the → H-R diagram (→ Humphreys-Davidson limit). Yellow hypergiants have high → mass loss rates (10-5-10-3 solar masses per year) and are in a short, transitional evolutionary stage. Their evolutionary state is thought to correspond to post-red supergiants rapidly evolving in blueward loops in the H-R diagram. In their post-RSG blueward evolution these stars enter a temperature range (6000-9000 K), called → yellow void, with increased dynamical instability. Their link to other advanced evolutionary phases of massive stars such as → Luminous Blue Variables and → Wolf-Rayet stars is still an open issue in stellar evolution theory. The most famous yellow hypergiant is → Rho Cassiopeiae.

yellow; → hypergiant.

yellow supergiant (YSG)
  اَبَر-غول ِ زرد   
abarqul-e zard (#)

Fr.: supergéante jaune   

A supergiant star of type F and G whose effective temperature is between 4800 and 7500 K. Yellow supergiants are extremely rare, because they represent a very short-lived phase, typically a few tens of thousands of year, in the evolution of → massive stars.

yellow; → supergiant.

yellow void
  تهی ِ زرد   
tohi-ye zard

Fr.: lacune jaune   

A temperature range (6000-9000 K) in the → H-R diagram occupied by → yellow hypergiants in their post-RSG blueward evolution, where high → mass loss episodes occur.

yellow; → void.

yellowcake
  کیک ِ زرد   
keyk-e zard

Fr.: yellow cake, "gâteau jaune"   

The final product obtained from the processing of uranium ores. It is a coarse powder, a mixture of uranium oxides, with about 80% U3O8. It has a pungent odor and melts at approximately 2878 °C. The yellowcake produced by most modern mills is actually brown or black, not yellow; the name comes from the color of the concentrates produced by early mining operations due to impurities from ammonium diuranate. Yellowcake must be converted into → uranium hexafluoride (UF6) before it can be enriched, the process that makes the sort of uranium used by nuclear power plants or bomb-makers (→ uranium enrichment). The uranium hexafluoride is heated to become a gas and loaded into cylinders. When it cools, it condenses into a solid.

yellow; cake, M.E., from O.Norse kaka "cake," from which also derive M.Du. koke, Du. koek, Ger. Kuchen.

Yerkes refractor
  شکست‌گر ِ یرکیز   
šekastgar-e Yerkes

Fr.: réfracteur de Yerkes   

The largest → refracting telescope and the last of the great refractors with a lens diameter of 102 cm (f/d = 19), completed in 1897. The lens was ground by American telescope builders Alvan Clark & Sons. Used mainly for both visual and photographic studies of double stars, it is typical of the long-tube refractors traditionally employed in such work.

After Yerkes Observatory; → refractor.

Yerkes system
  راژمان ِ یرکیز   
râžmân-e Yerkes

Fr.: système de Yerkes   

Same as → Morgan-Keenan classification.

After Yerkes Observatory, where the classification was developed; → system.

yield
  ۱) بازده؛ ۲) وادهی، واداد   
1) bâzdeh (#); 2) vâdehi, vâdâd

Fr.: 1) rendement; 2) limite d'élasticité   

1a) Chemistry: The quantity of product resulting from a chemical reaction or process, generally expressed as a percentage of the amount that is theoretically obtainable.
1b) Nuclear physics: 1) The number of → daughter atoms produced by the decay of one atom of a → parent radioactive element. For example, the → fission of one atom of 238U produces an average 0.0063 atoms of 136Xe, denoted: Y (136Xe)238 = 0.0063.
1c) A measure of the destructive energy of a nuclear explosion, expressed in kilotons of the amount of → T.N.T. that would produce the same destruction.
1d) → quantum yield.
2) → yield point.

M.E.; O.E. geldan, gieldan "to pay;" cf. O.S. geldan "to be worth," M.Du. ghelden, Du. gelden "to cost, be worth," O.H.G. geltan, Ger. gelten "to be worth."

1) Bâzdeh "yield, return," from bâz- "anew, again," → re- + deh present stem of dâdan "to give" (Mid.Pers. dâdan "togive, create;" O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives;" Skt. dadáti "he gives;" Gk. tithenai "to place, put, set," didomi "I give;" L. dare "to give, offer," facere "to do, to make;" Rus. delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do;" PIE base *dhe- "to put, to do").
2) Vâdehi, vâdâd, verbal noun from vâdâdan "to surrender," from vâ-, → de-, + dehi, dâd, from dâdan, as above.

yield point
  نقطه‌ی ِ وادهی، ~ واداد   
noqte-ye vâdahi, ~ vâdâd

Fr.: limite d'élasticite   

The point at which the → strain caused by a → stress on a material begins to increase without further increase in the stress. This point marks the end of → elastic deformation and the beginning of → plastic deformation. Same as → elastic limit.

yield; → point.

ylem
  ایلم   
ilem

Fr.: ylem   

The term first used by George Gamow (1904-1968) in a paper (Physical Review, 1948, coauthored by Alpher and Bethe) to describe the → primordial → substance from which the → chemical elements were formed. It fell into disuse.

M.E. ylem, from O.Fr. ilem "universal matter," from M.L. hyle "matter," from Gk. hule "matter, material, woods," used by Aristotle as perote hule "fundamental matter, raw material."

yocto- (y-)
  یوکتو-   
yokto-

Fr.: yocto-   

A metric prefix denoting 10-24. As of 2007, yocto- is the smallest SI prefix to be approved.

From L. octo, Gk. okto "eight," because it is equal to 1/10008.

yoke
  یوغ   
yuq (#)

Fr.: joug   

A device for joining together a pair of draft animals, especially oxen, usually consisting of a crosspiece with two bow-shaped pieces, each enclosing the head of an animal (dictionary.com).
yoke mounting.

M.E.; O.E. geoc "yoke," earlier geoht (cf. O.S. juk, Dan. aag, M.Du. joc, Du. juk, O.H.G. joh, Ger. joch, Goth. juk "yoke"); cognate with Pers. yuq, as below

Yuq "yoke," variants yuj, juh, jut, jot; Mid.Pers. jug, ayoxtan "to join, yoke;" Av. yaog- "to yoke, put to; to join, unite;" cf. Skt. yugam "yoke;" Hittite yugan "yoke;" Gk. zygon "yoke," as above, zeugnyanai "to join, unite;" L. jungere "to join," O.C.S. igo, O.Welsh iou, Lith. jungas O.E. geoc, as above; PIE base *yeug- "to join."

yoke mounting
  برنشاند ِ یوغی   
barnešând-e yuqi

Fr.: monture anglaise à berceau   

A form of → English mounting in which the → telescope is suspended inside an inclined fork, supported at both ends, and forming a → right ascension axis parallel to the Earth's → axis. The telescope pivots about the → declination axis inside two parallel forks.

yoke; → mounting.

YORP effect
  اُسکر ِ YORP   
oskar-e YORP

Fr.: effet YORP   

A phenomenon in which the rotation rate of a small asteroid changes under sunlight absorption. Photons from the Sun are absorbed by a small body and reradiated in infrared. In the process, two forces influence the object: one from the impact of the photons, providing a tiny push, and the other as a recoil effect when the object emits the absorbed energy. In the YORP effect the body's shape has a more effective role than albedo in altering the spin rate. For small asteroids (< 10 km), YORP can cause measurable changes in rotation rate. The effect can even speed up the rotation leading to disintegration. → Yarkovsky effect.

Short for Ivan Osipovich Yarkovsky, John A. O'Keefe, V. V. Radzievskii, and Stephen J. Paddockk, who developed the explanation; → effect.

yotta- (Y-)
  یوتا-   
yotta-

Fr.: yotta-   

A metric prefix denoting 1024.

On the model of → yocto-.

young
  جوان   
javân

Fr.: jeune   

Being in the first or early stage of existence or evolution; e.g. → young stellar object.

M.E.; O.E. geong "youthful, young," from P.Gmc. *jungas (cf. O.S., O.Fris. jung, O.N. ungr, M.Du. jonc, Du. jong, O.H.G., Ger. jung, Goth. juggs), from PIE base *yeu- "vital force, youthful vigor;" cognate with Pers. javân, as below.

Javân "young;" Mid.Pers. juwân "young, youth;" Arm. yavanak (loaned from Mid.Pers.); Av. yuuan- "youth;" cf. Skt. yuvan- "young, youth;" L. juvenis "young man;" Lith. jaunas "young;" O.C.S. junu, Rus. junyj "young;" cognate with E. young, as above.

young stellar object (YSO)
  بر آخت ِ ستاره‌ای ِ جوان   
barâxt-e setâreyi-ye javân

Fr.: objet stellaire jeune   

Any star that has evolved past the → protostar stage, but has not yet arrived on the → main sequence. There is a variety of YSOs depending on their age, mass, and environment, including → Herbig stars, → T Tauri stars, and, in general, compact infrared sources embedded in molecular clouds.

young; → stellar; → object.

Young's experiment
  آزمایش ِ یانگ   
âzmâyeš-e Young (#)

Fr.: expérience de Young   

A method of producing → interference of light. Two beams of → coherent light are produced by passing light through a very small circular aperture in one screen, then through two small circular apertures very close together in a second screen. On a third screen, behind the second screen, there will be two overlapping sets of waves and, if the light is monochromatic, → interference fringes will appear on the third screen. The experiment can also be performed with a beam of electrons or atoms, showing similar interference patterns. Young's experiment provides an evidence of the → wave-particle duality, as explained by → quantum mechanics. Same as → double-slit experiment.

Named after the English scientist Thomas Young (1773-1829), who originally performed the experiment some time around 1801 in an attempt to resolve the question of whether light was composed of particles (the → corpuscular theory of light); or rather consisted of waves travelling through some → ether. The experiment proved the wave nature of light; → experiment.

Young's modulus
  پیمون ِ یانگ   
peymun-e Young

Fr.: module de Young   

A measure of elasticity of a material, defined as the ratio of tensile → stress to tensile → strain, which equals the ratio of compressive stress to compressive strain.

Named after Thomas Young, → Young's experiment.

<< < -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 cri cro cub cur cyc cyl dar dat daw de- Deb dec dec dee def deg del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis div dog Dop dou dra dua dus dwa dyn e-m ear ecl eco eff ein Ein elb ele ele ele ele Els emi emp ene enr env epi equ equ Eri est Euc eva evo exc exc exh exo exp exp ext ext f-n Fah fam fau fee Fer fib fil fin fir fix fle flu foc for for for fra fre fre fri fun fuz gal gal gal Gan gau GCN gen geo geo geo geo Gl glo gra gra gra gra gra gre gro GW1 hab hal han HAR haz hea hel hel Hen Her heu Hig Hil hol hop hor hou Hub Hum Hyd hyd hyd hyp hys ide ign ima imp imp inc inc ind ine inf inf inf inh INP ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jos Jun K2 Kep key kin Kol lag lam Lan lar las lav lea leg len lev lig lim lin lin lin lis lob loc log lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal mar mas mas mat max mea mea mee Men mer met met met mic mid Mil min Mir mix mod mod mol mon Mor mou mul muo mys nan nat nav nec Nep neu New New NGC nob nom non non nor not nuc nuc num Nyq obj obs obs oce oen OH omn opa ope opt opt opt orb ord Ori ort osc out ove oxy pal pan par Par par par pas pea Pen per per per per per pet pha pho pho pho phy pie Pit Pla pla pla pla ple Poi pol pol pol pol pop pos pos pow pre pre pre Pre pri pri pri pro pro pro pro pro pro Pro pub pul pyr qua qua qua qua Qui rad rad rad rad rad rad ram ran rat rea rec rec rec red ref ref reg reg rel rel rem rep res res res ret rev rho Rie rim riv rol Ros rot rul S a Sah san Sat sca Sch Sch scr sec sec sec sei sel sem sep set sha she sho sid sig sil sim sin sit sky slu sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spl spr sta sta sta sta sta ste ste sti sto str str sub sub sub sug sun sup sup sup sup sur syl syn sys tal Tay tel ten ter tex the the the thi tho thu tid tim tod top tot tra tra tra tra tri tri tro tru tur twi Typ UFO ult unc uni uni uni upg ura uti val var vec vel ver ver vig vir vis voc von wak Was wav wax wea wei whi Wie win WN6 wom X-r yel you zer zod > >>