<< < -es -iv -ti 21- a p abe abs abs acc acc acc act act ada adi ads aes Age Alb Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app app arb are ari art ass ast ast ast Atl ato ato Aug aut Avo azi bac bal ban bar bas bea bel Bet bia Big bin bio bir bla bla blo blu Boh Bon bot Bow bre Bri bro but cal cal Can Cap car cas cat cau cel cen cen cha cha cha che Chi chr cir cir civ Cla clo clu CNO coa coe coi 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 cyl dar dat Daw de- Deb dec dec def def deg Del den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis diu dog Dop dou Dra dua dus dwa dyn e-f Ear ecl eco edu eig Ein ela ele ele ele Ele elo emi emp ene Enl env epi equ equ erg est Euc eva evo exa exc exe exo exp exp ext ext f m fac fal fas fee Fer fib fie fin Fir fix fle flu foc for for For fou Fra fre Fri ful fuz Gal Gal gal Gam gas Gau gen geo geo geo geo Gib glo gov gra gra gra gra gre gro gul H-b hal Ham har Hay hea hel hel hem her het Hig hik hol hom hor hot Hub hum hyb hyd hyd hyp hyp ide ign ima imp imp imp inc ind ind ine inf inf inf ini ins ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jos jun K-T Kep key kin Kol lad Lam lan lar las lat lea leg len lev lig lik lin lin lin Lis lob loc log loo low lum lun lun Lym Mac Mag mag mag mag mag Mag mak map Mar mas mat mat mea mea med mem mer MES met met MHD mic mid mil min mis mix mod mol mom Moo mos Mu mul mus nab nar nat neb neg nes neu New New nig nod non non non Nor noz nuc nul num OB obl obs Occ oct off Ohm on- ope Opp opt opt orb orb org Ori ort osm out ove ozo pal pap par par par pas pat pec pen per per per per per pH pha pho pho pho phy pie pla Pla Pla pla pla Plo poi pol pol pol pol por pos pot 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 Ré 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 Sag sam sat sca Sch Sch sco sec sec sec seg sel sem sen set sha Sha sho SI sid sil sim sin sis sky slo sna Soc sol sol sol Sol Som sou spa 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 sys tan Tay Tem ten ter The the the the thi thr tic tid tim Tol tor tot tra tra tra tra Tri tri tro tru tur two Typ UHE ult unc uni uni uni upg ura uti val var vec vel ver ver vig vir vis VLT vol wad was wav wav wea wei Whe Wie win WN5 Wol WZ Yag yot zen zir > >>
dust feature ârang-e qobâr Fr.: marque de poussière, signature de ~, motif spectral de ~ An emission or absorption mark in the spectrum of an astronomical object, the origin of which is attributed to the presence of dust in the object or on the line of sight. |
dust grain dâne-ye qobâr (#) Fr.: grains de poussière A small, solid flake of → graphite and/or → silicates coated with water ice, found in the → interstellar medium or the → interplanetary medium. Dust grains are irregularly shaped with sizes from microns to Angstroms (→ very small grain; → big grain; → PAH). It is believed that the dust is mainly formed in the cool outer layers of → red giants and dispersed in the interstellar medium. In dense environments, such as → molecular clouds and around → protostars, dust grains grow due to collisions (→ grain growth). Therefore, dust grains in → protostellar disks should be larger than interstellar grains. Dust grains absorb and scatter optical and ultraviolet light and re-radiate in infrared (→ dust emission). Dust acts as a catalyst in the interstellar medium, because molecules form via reactions on the surface of dust grains. |
dust lane bârike-ye qobâr Fr.: bande de poussière A narrow, elongated structure of absorbing matter seen running over extended emission objects such as nebulae and galaxies. → dust; lane, from O.E. lane, lanu "narrow hedged-in road," cf. Du. laan "lane," O.N. lön "row of houses," of unknown origin. Bâriké "a narrow thing," from bârik "narrow," from Mid.Pers. bārīk "narrow," Av. bāra-, as in tiži.bāra- "sharp-edged," from brāy- "to cut," Mod.Pers. bor-, boridan "to cut;" qobâr→ dust. |
dust model model-e qobâr Fr.: modèle de poussière A model of → dust grains conceived to describe the observed → interstellar extinction properties. It is characterized by the abundance of the different → chemical elements locked up in the dust, and by the → composition, → morphology, and → size distribution of its individual grains. For example, → MRN dust model. |
dust obscuration tirešod pat qobâr Fr.: obscurcissement par la poussière The → absorption of → electromagnetic radiation from an astrophysical object by → dust grains associated with that object. → dust; → obscuration. Tiregi, → obscuration, pat, → by; qobâr, → dust. |
dust scattering parâkaneš-e qobâri, ~ pat qobâr Fr.: diffusion par la poussière The scattering of → photons by → dust grains. → dust; → scattering. |
dust settling niyâšeš-e qobâr Fr.: dépose de poussières A process occurring in → protoplanetary disks whereby relatively large → dust grains settle to the disk midplane. These grains, with sizes from → micron to → millimeter, grow from smaller dust grains and will eventually give rise to a planetary system. |
dust storm qobâr-tufân Fr.: tempête de poussière An unusual, frequently severe weather condition characterized by strong winds and dust-filled air over an extensive area. See also → dust devil, → dust whirl. |
dust tail donbâle-ye qobâri (#) Fr.: queue de poussière The tail of a → comet which is caused by → solar radiation pressure forcing the dust particles away from the → coma in a curved arch. Also called a → Type II tail. |
dust temperature damâ-ye qobâr Fr.: température de poussière An indication of the heat amount received by → dust grains from the ambient → radiation field. Dust temperature depends on the optical properties and → sizes of grains (i.e., on the way they → absorb and → emit radiation) as well as on the → interstellar radiation field. Most of the visible and → ultraviolet radiation in galaxies from stars passes through clouds of particles and heats them. This heating leads to re-radiation at much longer wavelengths extending to the millimeter. → dust; → temperature. |
dust whirl 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-driven wind 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. |
duty harg (#) Fr.: devoir 1) Something that one is expected or required to do by moral or legal
→ obligation. 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 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. 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 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 elliptical galaxy 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 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 irregular galaxy 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 nova 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 planet 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. |
<< < -es -iv -ti 21- a p abe abs abs acc acc acc act act ada adi ads aes Age Alb Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app app arb are ari art ass ast ast ast Atl ato ato Aug aut Avo azi bac bal ban bar bas bea bel Bet bia Big bin bio bir bla bla blo blu Boh Bon bot Bow bre Bri bro but cal cal Can Cap car cas cat cau cel cen cen cha cha cha che Chi chr cir cir civ Cla clo clu CNO coa coe coi 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 cyl dar dat Daw de- Deb dec dec def def deg Del den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis diu dog Dop dou Dra dua dus dwa dyn e-f Ear ecl eco edu eig Ein ela ele ele ele Ele elo emi emp ene Enl env epi equ equ erg est Euc eva evo exa exc exe exo exp exp ext ext f m fac fal fas fee Fer fib fie fin Fir fix fle flu foc for for For fou Fra fre Fri ful fuz Gal Gal gal Gam gas Gau gen geo geo geo geo Gib glo gov gra gra gra gra gre gro gul H-b hal Ham har Hay hea hel hel hem her het Hig hik hol hom hor hot Hub hum hyb hyd hyd hyp hyp ide ign ima imp imp imp inc ind ind ine inf inf inf ini ins ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jos jun K-T Kep key kin Kol lad Lam lan lar las lat lea leg len lev lig lik lin lin lin Lis lob loc log loo low lum lun lun Lym Mac Mag mag mag mag mag Mag mak map Mar mas mat mat mea mea med mem mer MES met met MHD mic mid mil min mis mix mod mol mom Moo mos Mu mul mus nab nar nat neb neg nes neu New New nig nod non non non Nor noz nuc nul num OB obl obs Occ oct off Ohm on- ope Opp opt opt orb orb org Ori ort osm out ove ozo pal pap par par par pas pat pec pen per per per per per pH pha pho pho pho phy pie pla Pla Pla pla pla Plo poi pol pol pol pol por pos pot 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 Ré 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 Sag sam sat sca Sch Sch sco sec sec sec seg sel sem sen set sha Sha sho SI sid sil sim sin sis sky slo sna Soc sol sol sol Sol Som sou spa 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 sys tan Tay Tem ten ter The the the the thi thr tic tid tim Tol tor tot tra tra tra tra Tri tri tro tru tur two Typ UHE ult unc uni uni uni upg ura uti val var vec vel ver ver vig vir vis VLT vol wad was wav wav wea wei Whe Wie win WN5 Wol WZ Yag yot zen zir > >>