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 p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut aut axi Baa bal Bal bar bar bea beh Bes bia big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo Cal cal Can cap car Car cat cat CCD Cen cen CGS cha cha che che chr cir cir cis 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 con Cop Cor cor cor cos cos Cou cou cov cre cri cro cry cur cut Cyg DA dar dat de deb dec dec ded def def dei dem den dep des det dev dia dif dif dig Dio Dir dis dis dis dis dis dis div dom dou dow dri dur dus dyn dyn ear eav ecl Edd eff Ein Ekm ele ele ele ele ell emb emi enc ene ent eph equ equ equ eru eth eup eve EX exc exe exi exo exp ext ext ext fab fai far Fec fem fer fie fin fir fis fla flo flu foc for for Fou fra fre fre fro fun G r Gal gal gam gas Gau gel gen geo geo geo Gho gla goa gra gra gra gra gre Gre gro gyr had hal har har HD Hea Hel hel Her her hid hig hip hol hor hos hov Hub Hun hyd hyd hyd hyp IC ide ill ima imp imp inc inc ind ind inf inf inf inf inj InS ins int int int int int int int int int inv ion iro ise iso iso ite jet Jou Jup kap Kep kil Kip 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 mea med men mer Mes met met mic Mic Mie Mil min mis mJy mod mol mon moo mot mul mul mut nad nas nat neb neg net neu New New nig Noe non non non Nor nov nuc nul num OB obl obs occ Ock off Ohm on- ope opi opt opt orb orb ord Ori ort osm out ove ozo pal pan par par par par pat pec pen per per per per per Pfu 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 rai ran Ras Ray rea rec rec rec red red ref reg reg rel rel rel rep res res res res Reu rhe Rie rig ris Roe Ros rot Rud ryd Sag sam sat sca sca Sch sci Sea sec sec see sel sem sen ser Sey Sha she sho sid sig sim sim sin ske sle smo Sob sof sol sol sol sol sou Sou spa Sp spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver ver vin vir vis Vog von wal wat wav wax wea wei Whi wil win WN7 wor X-r Yar You zer zod > >>

Number of Results: 13070 Search : far
dust whirl
  غبارگرد   
qobârgard

Fr.: tourbillon de poussière   

A rapidly rotating column of air (whirlwind) over a dry and dusty or shady area, carrying dust, leaves, and other light material picked up from the ground (Meteorology Glossary, Amer. Meteo. Soc.). See also → dust devil, → dust storm.

dust; → whirl.

dust-driven wind
  باد ِ غبار‌زاد   
bâd-e qobârzâd

Fr.: vent induit par poussière   

A → stellar wind generated by the action of → radiation pressure on dust grains. This occurs in the case of cool stars, such as → AGB stars, with → effective temperatures below 2500 K when the density is sufficiently large. Since dust is a very good continuum absorber, the dust grains will be radiatively accelerated outward.

dust; → drive; → wind.

duty
  هرگ   
harg (#)

Fr.: devoir   

1) Something that one is expected or required to do by moral or legal → obligation.
2) The binding or obligatory force of something that is morally or legally right; moral or legal obligation.
3) An → action or → task required by a person's position or occupation; → function (Dictionary.com).

M.E. du(e)te, from Anglo-Fr. duete, from O.Fr. deu "due, owed; proper, just," from V.L. *debutus, from L. debitus, p.p. of debere "to owe."

Harg, from Mid.Pers. harg, halg "duty, tribute; work, effort;" akin to Mod.Pers. gahulidan "to exchange, barter," → exchange; cf. Wakhi (y)ark "work, matter, business", Yaghnobi ark "work, matter, business," Yighda hor, Munji hôr(g) "work;" Proto-Ir. *harH- "to pay tribute; to barter, trade, exchange;" cognate with Gk. elein "to take (by force)," elor "loot, looty, catch;" E. to sell (Cheung 2006).

dwarf
  کوتوله   
kutulé (#)

Fr.: nain   

1) General: A person of abnormally small height owing to a pathological condition; an animal or plant much smaller than the average of its kind or species.
2) Astro.: An adjective characterizing a particular type of object, as in → dwarf star, → dwarf galaxy, → dwarf planet.
See also:
blue compact dwarf galaxy, → brown dwarf, → brown dwarfcooling, → brown dwarfdesert, → DA white dwarf, → DB white dwarf, → DC white dwarf, → DO white dwarf, → double white dwarf, → DQ white dwarf, → Draco Dwarf, → dwarf Cepheid, → dwarf elliptical galaxy, → dwarf irregular galaxy, → dwarf nova, → dwarf spheroidal galaxy, → dwarf spiral galaxy, → dwarf starburst galaxy, → DZ white dwarf, → L dwarf, → M dwarf, → OB subdwarf, → red dwarf, → Sagittarius Dwarf Elliptical Galaxy, → Sagittarius Dwarf Irregular Galaxy, → Sculptor Dwarf Elliptical Galaxy, → subdwarf, → T dwarf, → tidal dwarf galaxy, → white dwarf, → white dwarf cooling track, → white dwarf crystallization, → Y dwarf.

Dwarf, from ME dwerg, dwerf, O.E. dweorg, dweorh, O.H.G. twerg "dwarf," from P.Gmc. *dweraz.

Kutulé, from kut "small, short" + Pers. diminutive suffix -ulé, → -ula. The first component kut is the base of kutâh "short, small, little," kudak "child, infant," Mid.Pers. kôtâh "low," kôtak "small, young; baby;" the Mid/Mod.Pers. kucak "small," belongs to this fammily; Av. kutaka- "little, small."

dwarf Cepheid
  کفیءوسی ِ کوتوله   
Kefeusi-ye kutulé

Fr.: céphéide naine   

An old name for a class of pulsating variable stars with small variations in amplitude, also called an AI Velae star or delta Scuti star. They lie in the lower part of the Cepheid instability strip.

dwarf; → Cepheid.

dwarf elliptical galaxy
  کهکشان ِ بیضی‌گون ِ کوتوله   
kahkašân-e beyzigun-e kutulé (#)

Fr.: galaxie elliptique naine   

A galaxy that is much smaller than other members of the elliptical class; it is designated as dE. A subtype of dwarf ellipticals is called a → dwarf spheroidal galaxy (dSph). The basic characteristics of the class are low surface brightness and smooth light distribution. They range in luminosity from that of the faintest dSph galaies MV ~ -9 to about -17. In the → Local Group there are 19 known dEs. They are very common in → galaxy clusters.

dwarf; → elliptical; → galaxy.

dwarf galaxy
  کهکشان ِ کوتوله   
kahkešân-e kutulé (#)

Fr.: galaxie naine   

A small, low luminosity galaxy that is associated with a larger spiral galaxy and may make up part of a galactic halo. There are many of them in the Local Group, and often orbit around larger galaxies such as the Milky Way and the Andromeda Galaxy. There are three main types of them: → dwarf elliptical galaxy (dE), → dwarf irregular galaxy (dI), and → dwarf spiral galaxy (dSA).

dwarf; → galaxy.

dwarf irregular galaxy
  کهکشان ِ بی‌سامان ِ کوتوله   
kahkašân-e bisâmân-e kutulé

Fr.: galaxie irrégulière naine   

An irregular galaxy that is much smaller than other irregulars. Dwarf irregulars are generally metal poor and have relatively high fractions of gas. They are thought to be similar to the earliest galaxies that populated the Universe, and are therefore important to understand the overall evolution of galaxies.

dwarf; → irregular; → galaxy.

dwarf nova
  نووای ِ کوتوله، نو‌اختر ِ ~   
novâ-ye kutulé, nowaxtar-e ~

Fr.: nova naine   

A class of → novae and → cataclysmic variables that have multiple observed → eruptions. Their prototype is → U Geminorum star. Optically, dwarf nova eruptions have amplitudes of 2-6 mag in V, a duration of a few to 20 days and a recurrence time-scale of weeks to years. Dwarf novae are thought to be → semidetached binary stars consisting of a → white dwarf  → primary accreting via → Roche lobe overflow from a → companion which is usually a → late-type, generally → main-sequence star. DN outbursts are usually attributed to the release of gravitational energy resulting from an → instability in the → accretion disk or by sudden mass transfers through the disk.

dwarf; → nova.

dwarf planet
  سیاره‌ی ِ کوتوله   
sayyâre-ye kutulé (#)

Fr.: planète naine   

A new category of → astronomical objects in the → solar system introduced in a resolution by the 26th General Assembly of the → International Astronomical Union (IAU) on August 24, 2006. The characterizing properties are as follows: 1) It is in orbit around the Sun; 2) It has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a → hydrostatic equilibrium (nearly round) shape; 3) It has not "cleared the neighbourhood" around its orbit; and 4) It is not a → satellite of a → planet, or other non-stellar body. The property 3 reclassified → Pluto from a planet to a dwarf planet because it has not cleared the neighborhood of its orbit (the → Kuiper Belt). The largest known dwarf planets are: → Eris, → Pluto, → Ceres, → Makemake, and → 2015 RR245.

dwarf; → planet.

dwarf spheroidal galaxy (dSph)
  کهکشان ِ کره‌وار ِ کوتوله   
kahkašân-e korevâr-e kutulé (#)

Fr.: galaxie sphéroïdale naine   

A subtype of dwarf ellipticals (→ dwarf elliptical galaxy), which are companion to the → Milky Way and other similar galaxies. The first example of such objects was discovered by Harlow Shapley (1938) in the constellation → Sculptor. 22 such galaxies are known currently to orbit the Milky Way and at least 36 exist in the → Local Group of galaxies. Nearby → galaxy clusters such as the → Virgo, → Fornax, → Centaurus, and → Coma clusters contain hundreds to thousands of individual dSph galaxies. These galaxies have very low → surface brightnesses, as low as only 1% that of the → sky background. They are also among the smallest, least luminous galaxies known. Most of the radiation from dSph galaxies is emitted by stars in the optical portion of the → electromagnetic spectrum. The lack of strong → emission lines, → infrared, or → radio emission suggests that these galaxies are generally devoid of → interstellar medium. The velocities of stars within dSph galaxies are so high that them must be disrupting. However, the bulk of mass in these galaxies might be undetected. Dynamical models that include → dark matter do adequately explain the → velocity dispersion of the stars in all dSph systems. In the most extreme cases, only 1% of the mass of the galaxy is visible. Many of the Local Group dSph galaxies show evidence for → star formation more recent than 10 Gyr.

dwarf; → spheroidal; → galaxy.

dwarf spiral galaxy
  کهکشان ِ مارپیچ ِ کوتوله   
kahkašân-e mârpic-e kutulé (#)

Fr.: galaxie spirale naine   

A galaxy that belongs to the spiral class but is significantly smaller.

dwarf; → spiral; → galaxy.

dwarf star
  ستاره‌ی ِ کوتوله   
setâre-ye kutulé (#)

Fr.: étoile naine   

A star that burns its hydrogen content to produce its energy and therefore belongs to the main-sequence luminosity class.

dwarf; → star.

dwarf starburst galaxy
  کهکشان ِ کوتوله‌ی ِ ستاره-بلک   
kahkešân-e kutule-ye setâre-belk

Fr.: galaxie naine à flambée d'étoiless   

A → starburst galaxy that is a → dwarf galaxy. Examples include: the → dwarf irregular galaxy IC 10, the compact dwarf irregular Henize 2-10, and the dwarf irregular galaxy NGC 5253.

dwarf; → starburst; → galaxy.

dynamic
  توانیک   
tavânik

Fr.: dynamique   

1) Involving or relating to force related to motion.
2) Pertaining to the science of → dynamics.

From Fr. dynamique, from Ger. dynamisch, introduced by Leibnitz in 1691, from Gk. dynamikos "powerful," from dynamis "power," from dynasthai "be able to have power" + → -ic.

Tavânik, from tavân "power, strength," tavânestan "to be powerful, able," + Pers. suffix -ik; → -ics. The first component from Mid.Pers. tuwan "power, might," from O.Pers./Av. base tav- "to have power, to be strong, to be able," Av. tavah- "power," təviši- "strength," Mod.Pers. tuš, tâb "power, ability," O.Pers. tauman- "power, strength," tunuvant- "powerful," Skt. tu- "to be strong, to have authority," tavas-, tavisa- "strong, energetic," tavisi- "power, strength" + -ik-ic.

dynamic equilibrium
  ترازمندی ِ توانیک   
tarâzmandi-ye tavânik

Fr.: équilibre dynamique   

Mechanics: The condition of a moving mechanical system when the accelerating force is balanced by an imaginary kinetic reaction according to → d'Alembert's principle. See also → static equilibrium; → thermodynamic equilibrium.

Dynamic, adj. from → dynamics; → equilibrium.

dynamic oblateness
  پخی ِ توانیک   
paxi-ye tavânik

Fr.: aplatissement dynamique   

A measure of the extent to which mass has been shifted from the polar regions of a (spinning) body toward its equator (Ellis et al., 2007, Planetary Ring Systems, Springer).

dynamic; → oblateness.

dynamic pressure
  فشار ِ توانیک   
fešâr-e tavânik

Fr.: pression dynamique   

A property of a moving → fluid defined by (1/2)ρv2 in → Bernoulli's law, where ρ is → density of fluid and v is → velocity. Dynamic pressure is the difference between → total pressure and → static pressure. Also called → velocity pressure. → ram pressure.

dynamic; → pressure.

dynamic range
  برد ِ توانیک   
bord-e tavânik

Fr.: dynamique   

The ratio of the maximum to minimum signal levels present in an image. For instance, a true 12-bit digital camera is capable of providing a dynamic range of 4096 to 1.

Adj. of → dynamics; → range.

dynamic viscosity
  وشکسانی ِ توانیک   
vošksâni-y tavânik

Fr.: viscosité dynamique   

Same as → viscosity and → absolute viscosity.

dynamic; → viscosity.

<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut aut axi Baa bal Bal bar bar bea beh Bes bia big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo Cal cal Can cap car Car cat cat CCD Cen cen CGS cha cha che che chr cir cir cis 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 con Cop Cor cor cor cos cos Cou cou cov cre cri cro cry cur cut Cyg DA dar dat de deb dec dec ded def def dei dem den dep des det dev dia dif dif dig Dio Dir dis dis dis dis dis dis div dom dou dow dri dur dus dyn dyn ear eav ecl Edd eff Ein Ekm ele ele ele ele ell emb emi enc ene ent eph equ equ equ eru eth eup eve EX exc exe exi exo exp ext ext ext fab fai far Fec fem fer fie fin fir fis fla flo flu foc for for Fou fra fre fre fro fun G r Gal gal gam gas Gau gel gen geo geo geo Gho gla goa gra gra gra gra gre Gre gro gyr had hal har har HD Hea Hel hel Her her hid hig hip hol hor hos hov Hub Hun hyd hyd hyd hyp IC ide ill ima imp imp inc inc ind ind inf inf inf inf inj InS ins int int int int int int int int int inv ion iro ise iso iso ite jet Jou Jup kap Kep kil Kip 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 mea med men mer Mes met met mic Mic Mie Mil min mis mJy mod mol mon moo mot mul mul mut nad nas nat neb neg net neu New New nig Noe non non non Nor nov nuc nul num OB obl obs occ Ock off Ohm on- ope opi opt opt orb orb ord Ori ort osm out ove ozo pal pan par par par par pat pec pen per per per per per Pfu 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 rai ran Ras Ray rea rec rec rec red red ref reg reg rel rel rel rep res res res res Reu rhe Rie rig ris Roe Ros rot Rud ryd Sag sam sat sca sca Sch sci Sea sec sec see sel sem sen ser Sey Sha she sho sid sig sim sim sin ske sle smo Sob sof sol sol sol sol sou Sou spa Sp spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver ver vin vir vis Vog von wal wat wav wax wea wei Whi wil win WN7 wor X-r Yar You zer zod > >>