An Etymological Dictionary of Astronomy and Astrophysics
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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 ave axi Bab bal Bal bar bar bea Bek 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 CH cha cha che Che chr cir cir cit 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 Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa 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 vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>

Number of Results: 13048 Search : far
Wilkinson Microwave Anisotropy Probe (WMAP)
     
WMAP

Fr.: WMAP   

A space telescope launched by NASA in 2001 which measures the temperature fluctuations in the → cosmic microwave background (CMB) radiation. It creates a full-sky map of the CMB, with a 13 arcminute resolution via multi-frequency observations. WMAP is the first mission to use a → Lagrangian point L2 as its permanent observing station at a distance of 1.5 million km. WMAP completed its prime two years of mission operations in September 2003 and is continuing in 2009 its observations for still several years to come. WMAP's measurements have played a considerable role in establishing the current standard model of cosmology. They are consistent with a Universe that is dominated by → dark energy, with negative pressure or a → cosmological constant. In this model, the age of the Universe is 13.73 ± 0.12 billion years. The current expansion rate of the Universe measured by the Hubble constant, is 70.5 ± 1.3 km·s-1 Mpc-1. The content of the Universe consists of 4.56% ± 0.15% ordinary → baryonic matter, 22.8% ± 1.3% → cold dark matter, and 72.6% ± 1.5% of → dark energy, that accelerates the → expansion of the Universe.

WMAP, short for Wilkinson Microwave Anisotropy Probe, in honor of David Todd Wilkinson (1935-2002), who had been a member of the mission's science team.

Wilson depression
  نشیب ِ ویلسون   
našib-e Wilson

Fr.: dépression de Wilson   

The depression on the → Sun's → photosphere associated with → sunspots and involving the → Wilson effect. The measured depression values vary between about 700 and 2,000 km.

Wilson effect; → depression.

Wilson effect
  اسکر ِ ویلسون   
oskar-e Wilson

Fr.: effet de Wilson   

A phenomenon in which the shape of → sunspots flattens as they approach the → Sun's limb due to the → solar rotation. More specifically, when a sunspot approaches the → solar limbs the width of the → penumbra, relative to the → umbra, on the side facing the center of the Sun seems to become narrower than on the side facing the limb. This phenomenon arises from a projection effect, and is due to a geometrical depression (the → Wilson depression) in the layers of constant → optical depth in sunspots (see, e.g., Sami K. Solanki, 2003, Sunspots: An overview, The Astron. Astrophys. Rev., 11, 153).

First noticed by Alexander Wilson (1714-1786); → effect.

Wilson-Bappu effect
  اسکر ِ ویلسون-باپو   
oskar-e Wilson-Bappu

Fr.: effet de Wilson-Bappu   

The strong correlation between the equivalent width of Ca II → H and K lines of a late-type giant or supergiant star with the absolute visual magnitude of the star.

O. C. Wilson & M. K. Vainu Bappu (1957, ApJ 125, 661); → effect.

WIMP
  ویمپ   
WIMP (#)

Fr.: WIMP   

A member of a broad class of hypothetical elementary particles moving with non-relativistical speeds at the time of structure formation in the early Universe. WIMPs have nonzero rest mass and participate only in the weak nuclear interaction. WIMPs are expected to have collapsed into a roughly isothermal, spherical halo within which the visible portion of our galaxy resides. → dark halo. The → neutralino, predicted by supersymmetric theories is the favorite WIMP candidate. Another candidate is the → axion. WIMPs are candidates for dark matter.

weak; → interction; → massive; → particle .

wind
  ۱) باد؛ ۲) پیچیدن   
1) bâd (#); 2) picidan

Fr.: 1) vent; 2) s'enrouler   

1a) Meteo.: Air in motion, especially a natural and perceptible movement of air relative to the ground.
1b) Astro.radiation-driven wind; → solar wind; → Galactic wind; → stellar wind.
2) To change direction; turn; to have a circular or spiral course or direction; to coil or twine about something.

1) M.E., O.E. wind (cf. O.S., O.Fris., Du. wind, O.H.G. wind, Ger. Wind, Goth. winds).
2) M.E. windan, from O.E. windan "to turn, twist, curl," cognate with Du. winden, O.H.G. wintan, Ger. winden, from PIE *wendh- "to turn, wind, weave."

1) Bâd, from Mid.Pers. wâd "wind;" Av. vāta- "wind;" cf. Skt. vāta- "wind, god of wind;" Gk. anemos "wind;" L. ventus "wind" (Fr. vent); cognate with E. wind, as above.
2) Picidan "to twist, entwine, coil," → spiral.

wind accretion
  فربال ِ بادی، ~ پت باد   
farbâl-e bâdi, ~ pat bâd

Fr.: accrétion par vent   

A quasi-spherical accretion that is likely to occur in a → high-mass X-ray binary (HMXB) when the optical star of → early spectral class (O-B) does not fill its → Roche lobe, but has a significant → mass loss via → stellar wind. In → close binary systems another accretion regime, → disk accretion, occurs when the optical star overfills its Roche lobe.

wind; → accretion.

wind blanketing
  پتومندی ِ باد   
patumandi-ye bâd

Fr.: effet de couverture du vent   

A process whereby dense winds of very luminous O type stars modify the temperature and internal structure of the underlying photosphere by scattering back a considerable part of the coming photospheric radiation. Not to be confused with → line blanketing .

Thus called because the wind acts like a blanket and heats the photosphere * by reflecting its radiation; → wind.

wind clumping
  گوده‌داری ِ باد   
gudedâri-ye bâd

Fr.: grumelage de vent   

The inhomogeneous property of a → radiation-driven wind, or the physical mechanism accounting for the → clumped wind.

clumpy; → wind.

wind luminosity
  تابندگی ِ باد   
tâbandegi-ye bâd

Fr.: luminosité de vent   

The final kinetic energy of the → stellar wind expressed by: (1/2)Mdot.v2 = (1/2)(v/c)L For an O6 star, L ~ 3 x 105Lsun and v ~ 2000 km s-1, which give a wind luminosity of ~ 1 x 1037 erg s-1, about 1% of the → stellar luminosity. See also → photon tiring limit.

wind; → luminosity.

wind momentum
  جنباک ِ باد   
jonbâk-e bâd

Fr.: moment angulaire de vent   

The product of the → mass loss rate and → terminal velocity used in the → radiation-driven wind theory. See also → modified wind momentum.

wind; → momentum.

wind rose
  بادنقش   
bâdnaqš (#)

Fr.: rose des vents   

A diagram showing the relative frequency of winds blowing from each of the 8 or 16 main points of the compass, sometimes within specified speed ranges, at a given location over a considerable period.

Translation of Ger. Windrose "compass card," from Windwind + Rose "rose," → Rosette Nebula.

Bâdnaqš, from bâd, → wind, + naqš "painting, engraving, printing," → map.

wind vane
  بادنما   
bâdnemâ (#)

Fr.: girouette   

An object that is balanced on a rotating axis and indicates the direction of the wind. Also called a weather vane.

wind + vane "a blade, plate," O.E. fanafana "piece of cloth," O.H.G. fano, Ger. Fahne "flag, standard."

Bbâdnemâ "wind indicator," from bâd, → wind, + nemâ, from nemudan, → planetarium.

wind velocity
  تندای ِ باد   
tondâ-ye bâd

Fr.: vitesse de vent   

The speed at which the → stellar wind is forced away from the star. Wind velocities of → hot stars are directly measured from → P Cygni profiles, which indicate velocities from several hundred to several thousand km s-1. See also → escape velocity, → terminal velocity, → velocity law, → radiation-driven wind, → CAK model.

wind; → velocity.

winding problem
  پراسه‌ی ِ پیچش   
parâse-ye piceš

Fr.: problème d'enroulement   

The problem encountered in the explanation of the → spiral arms of galaxies if the material making up a spiral arm is static, that is remains in the arm. Since galaxies exhibit → differential rotation, stars near the center take less time to orbit the center than those farther from the center. The arm would, after a few → galactic rotations, become increasingly curved and wind around the → galaxy ever tighter until it ultimately disappears. This is inconsistent with observations.

window
  روزنه   
rowzané (#)

Fr.: fenêtre   

1) Anything likened to a window in appearance or function.
2) In particular, the wavelength region in the electromagnetic spectrum that is relatively unaffected by atmospheric absorption. → atmospheric windows; → infrared window; → optical window; → radio window.

Window literally "wind eye," from O.N. vindauga, from vindr, → wind, + auga, → eye.

Rowzané, from rowzan "window, aperture;" Mid.Pers. rocânak "window," rôšn "light; bright, luminous," from Av. raocana- "bright, shining, radiant," raocah- "light, luminous; daylight," related to Mod.Pers. ruz "day," from Mid.Pers. rôc, O.Pers. raucah-; akin to Skt. rocaná- "bright, shining," roka- "brightness, light;" Gk. leukos "white, clear;" L. lux "light" (also lumen, luna); PIE base *leuk- "light, brightness." The Persian words rowšan "bright, clear," foruq "light," and afruxtan "to light, kindle" also belong to this family, as well as the E. light, Ger. Licht, and Fr. lumière; forusorxinfrarouge.

window function
  کریای ِ روزنه   
karyâ-ye rowzané

Fr.: fonction fenêtre   

A function whose value is zero outside a given interval. Applications of window functions include signal filtering and spectral analysis. The various types of windw functions include: → rectangular window, cosine window, triangular window, Gaussian window, Hanning window, and so on.

window; → function.

wine
  می، باده، نبید   
mey (#), bâdé (#), nabid (#)

Fr.: vin   

The fermented juice of grapes, made in many varieties, such as red, white, sweet, dry, still, and sparkling, for use as a beverage, in cooking, in religious rites, etc., and usually having an alcoholic content of 14 percent or less (Dictionary.com).

M.E., O.E. win, cognate with O.H.G. win, Du. wijn, Ger. Wein, from L. vinum "wine," from PIE *woin-o-, related Gk. word oinos.

Mey, variant mol "wine;" Mid.Pers. mad, may "wine;" Av. maδu- "wine;" cf. Skt. madhu- "wine, sweet drink, sweet;" Gk. methy "wine;" O.C.S. medu; Lith. medus "honey;" O.Irish mid; Welsh medd; Breton mez "mead;" O.E. medu; E. mead "fermented honey drink;" Russ. medved "(honey-eater) bear."
Bâdé, from Mid.Pers. bâdag, from O.Pers. *bātu- "wine" (from bātu-gara- "cup, bowl"); cf. Khotanese Saka bātaa- "wine;" O.Pers. *batiaka- "cup, bowl" (cf. Pers. bâdiyé "bowl") loaned in Gk. batiaké "bowl, cup."
Nabid, "wine, date-wine," ultimately from Proto-Ir. *paH- "to drink;" cf. Av. paitīš- "drink" in vīspô.paitīš- "having all sorts of drinks;" pitu- "juice, food;" Wakhi puv-, pəv-, pit-; Sanglechi pöv-/pövδ- "to drink;" Skt. pā- "to drink;" Gk. pinein "to drink;" L. bibere "to drink," related to potare "to drink."

wing
  بال   
bâl (#)

Fr.: aile   

1) Either of the two limbs of a bird allowing her to fly. → Pegasus.
2) Either of the large flat structures in an aircraft's body that provide the main source of lift.
3) In spectroscopy, same as → line wing.

M.E. wenge from O.N. vængr "wing of a bird, aisle, etc." (cf. Dan., Swed. vinge "wing").

Bâl "wing," Mid.Pers. bâl, variant of par / parr "feather, " with the conversion of p to b and r to l; Av. parəna- "feather;" cf. Skt. parnam; O.H.G. farn "fern;" PIE pornom "feather."

Wing-Ford band
  باند ِ وینگ-فورد   
bând-e Wing-Ford

Fr.: bande de Wing-Ford   

A spectral feature at 9850-10200 Å appearing in the spectrum of some late-type → M dwarfs. It is attributed to iron hybrid (FeH), a typical signature of the atmospheres of the coolest stars.

First detected by R. F. Wing and W. K. Ford (1969, PASP 81, 527); → band.

<< < -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 ave axi Bab bal Bal bar bar bea Bek 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 CH cha cha che Che chr cir cir cit 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 Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa 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 vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>