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
WN6 star
  ستاره‌ی ِ WN6   
setâre-ye WN6

Fr.: étoile WN6   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N III 4634-4641, 5314 Å about N IV 3479-3484, 4058 Å and N V 3479-3484, 4058 Å present, but weak.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WN6ha
     
WN6ha

Fr.: WN6ha   

A → WNh type → Wolf-Rayet (→ WN6 star) with → absorption lines in its spectrum that have not been attributed to the presence of a → companion. For example → NGC 3603-A1.

The letter "a" indicating → absorption; → WNh type.

WN7 star
  ستاره‌ی ِ WN7   
setâre-ye WN7

Fr.: étoile WN7   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N III 4634-4641, 5314 Å stronger than N IV 3479-3484, 4058 Å, N III weaker than He II 4686 Å, He I weak with → P Cygni profile.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WN8 star
  ستاره‌ی ِ WN8   
setâre-ye WN8

Fr.: étoile WN8   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N III 4634-4641, 5314 Å very stronger than N IV 3479-3484, 4058 Å, N III about He II 4686 Å, and He I with → P Cygni profile.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WN9 star
  ستاره‌ی ِ WN9   
setâre-ye WN9

Fr.: étoile WN9   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N III 4634-4641, 5314 Å stronger than N II 3995 Å, N IV 3479-3484, 4058 Å absent, He I with → P Cygni profile.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WNE Wolf-Rayet
  وُلف-رایه‌ی ِ WNE   
Wolf-Rayet-e WNE

Fr.: Wolf-Rayet WNE   

In theoretical models, a → Wolf-Rayet star without hydrogen at its surface (< 10-5 in number) and with surface carbon abundance smaller than nitrogen abundance.

W short for Wolf-Rayet star, N for → nitrogen, E for early.

WNh type
  گونه‌ی ِ WNh   
guneh-ye WNh

Fr.: étoile de type WNh   

A → WN Wolf-Rayet star which is hydrogen rich. WNh stars are initially more massive and have lost relatively little mass compared to other WR stars. It is suggested that these types are core hydrogen burning → main sequence objects. The most massive stars currently known are all WNh stars rather than O-type main sequence stars.

WN, from → WN Wolf-Rayet; h, from → hydrogen.

WNL Wolf-Rayet
  وُلف-رایه‌ی ِ WNL   
Wolf-Rayet-e WNL

Fr.: Wolf-Rayet WNL   

In theoretical models, a → Wolf-Rayet star with hydrogen at its surface (> 10-5 in number). A star enters the Wolf-Rayet phase as a WNL, then may evolve through the sequence WNL → WNE, → WC, → WO. It can end its evolution at any of these stages.

W short for Wolf-Rayet star, N for → nitrogen, L for late.

WO Wolf-Rayet
  وُلف-رایه‌ی ِ WO   
Wolf-Rayet-e WO

Fr.: Wolf-Rayet WO   

A → Wolf-Rayet star whose spectrum shows emission lines of carbon and strong emission lines of oxygen O VI 3811-34 Å. In theoretical models, a W-R star whose carbon abundance at surface is larger than nitrogen abundance and has the abundance ratio (C + O) / He > 1 (in number).

W short for Wolf-Rayet star, O for → oxygen.

WO1 type
  ستاره‌ی ِ WO1   
setâre-ye WO1

Fr.: étoile WO1   

An oxygen-rich → Wolf-Rayet star whose spectrum shows the following emission line characteristics: No O IV 3400 Å, strong O VI 3811-34 Å, O V 5572-98 Å about or stronger than C IV 5801-12 Å, no C III 5696 Å.

W, from → Wolf-Rayet; O, from → oxygen; → star.

WO2 type
  ستاره‌ی ِ WO2   
setâre-ye WO2

Fr.: étoile WO2   

An oxygen-rich → Wolf-Rayet star whose spectrum shows the following emission line characteristics: No O IV 3400 Å, strong O VI 3811-34 Å, O V 5572-98 Å weaker than C IV 5801-12 Å, no C III 5696 Å.

W, from → Wolf-Rayet; O, from → oxygen; → star.

wobble
  ۱) پلاپلیدن؛ ۲) پلاپل   
1) palâpelidan; 2) palâpel

Fr.: chanceler, osciller, vaciller; chancellement, vacillement   

1a) To incline to one side and to the other alternately, as a wheel, top, or other rotating body when not properly balanced.
1b) To move unsteadily from side to side; vacillate; waver.
2) A wobbling movement (Dictionary.com).

Probably from Low Ger. wabbeln "to wobble;" cognate with O.N. vafla "hover about, totter," related to vafra "move unsteadily."

Palâpel "wobbling, unsteady motion" in štiyâni dialect, variant in colloquial Persian pilipili, pelpel (pilipili raftan, pilipili xordan).

Wolf minimum
  کمینه‌ی ِ ولف   
kamine-ye Wolf

Fr.: minimum de Wolf   

A 70-year period of unusually low → solar activity, from about 1280 to 1350. See also the → Maunder minimum.

Wolf number; → minimum.

Wolf number
  عدد ِ وُلف   
adad-e Wolf

Fr.: nombre de Wolf   

A number indicating the degree of → sunspot  → activity. Same as → sunspot number and → relative sunspot number.

Named after Johann Rudolf Wolf of Zurich who introduced the number in 1852; → number.

Wolf-Lundmark-Melotte (WLM)
  ولف-لوندمارک-ملوت   
Wolf-Lundmark-Melotte (WLM)

Fr.: Wolf-Lundmark-Melotte   

A → dwarf irregular galaxy that is a remote and rather isolated member of the → Local Group. Also known as DDO 221 and LEDA 143. It is a dim galaxy located in the constellation → Cetus, about three million → light-years from the → Milky Way. Its nearest neighbor, the → dwarf galaxy IC 1613, is one million light-years away. Quite elongated, with a largest extension of more than 8,000 light-years, WLM is about 12 times smaller than the Milky Way, a measurement that includes a → halo of extremely → old stars. WLM has a → metallicity only about one-tenth that of the Milky Way.

Named after astronomer Max Wolf (1863-1932), who discovered the galaxy in 1909, and astronomers Knut Lundmark (1889-1958) and Philibert Jacques Melotte (1880-1961), who identified it as a galaxy some fifteen years later.

Wolf-Rayet galaxy
  کهکشان ِ وُلف-رایه   
kahkešân-e Wolf-Rayet

Fr.: galaxie Wolf-Rayet   

A subset of → starburst galaxies whose integrated spectra show broad emission features attributed to the presence of hundreds to thousands → Wolf-Rayet stars. The most massive stars formed in the burst evolve rapidly into a substantial population of Wolf-Rayet stars in aggregations of ionized gas.

Wolf-Rayet star; → galaxy.

Wolf-Rayet star
  ستاره‌ی ِ وُلف-رایه   
setâre-ye Wolf-Rayet

Fr.: étoile Wolf-Rayet   

A type of very luminous, very hot (as high as 50,000 K) stars whose spectrum is characterized by broad emission lines (mainly He I and He II), which are presumed to originate from material ejected from the star at very high (~ 2000 km s-1) velocities. The most massive → O stars (M > 25 → solar masses for → solar metallicity) become W-R stars around 2 and 3 million years after their birth, spending only some few hundreds of thousands of years (≤ 106 years) in this phase until they explode as → type Ib and → type Ic supernovae. The minimum stellar mass that an O star needs to reach the W-R phase and its duration is dependent on → metallicity. → WC Wolf-Rayet; → WNE Wolf-Rayet; → WNL Wolf-Rayet; → WO Wolf-Rayet. For a review see: P. A. Crowther, 2007, Annu. Rev. of Astron. Astrophys. 45, 177.

Named after the French astronomers Charles Wolf (1827-1918) and Georges Rayet (1839-1906), of the Paris Observatory. In 1867 they discovered three stars in the constellation Cygnus (now designated HD191765, HD192103, and HD192641), that displayed broad emission bands in their spectra; → star.

Wollaston prism
  منشور ِ وُلاستون   
manšur-e Wollaston (#)

Fr.: prisme de Wollaston   

An optical device for producing and analyzing polarized light. It divides incoming unpolarized light into two orthogonal, linearly polarized beams. It consists of two prisms of either quartz or calcite cemented together.

After the English scientist William Hyde Wollaston (1766-1828); → prism.

Wolter telescope
  تلسکوپ ِ ولتر   
teleskop-e Wolter

Fr.: télescope Wolter   

A → grazing incidence telescope designed to observe → X-ray emission from astronomical objects. Wolter telescopes use a combination of two elements, a parabolic mirror followed by a hyperbolic mirror and come in three different optical configurations. The design most commonly used by X-ray astronomers is the Type I since it has the simplest mechanical configuration. In addition, the Type I design offers the possibility of nesting several telescopes inside one another, thereby increasing the useful reflecting area. This is an extremely important attribute, since virtually all X-ray sources are weak, and maximizing the light-gathering power of a mirror system is critical. The → Chandra X-Ray Observatory is a Wolter Type I telescope that has four thick nested mirrors coated in iridium. The Japanese X-ray observatory Suzuki uses a conical approximation of the Wolter Type I design. Its mirrors are coated in gold, and they are far thinner than the ones used in Chandra. This allows for denser nesting, so there are 700 mirrors instead of four. The result is a much higher collecting efficiency at a reduced weight. For comparable apertures and grazing angles, the primary advantage of Type II over Type I is that higher magnifications are attainable. This is because the second reflection is off the outside of a surface, which allows longer focal lengths. However, since off-axis images suffer much more severely from blurring in Type II configurations, the Wolter Type II is useful only as a narrow-field imager or as the optic for a dispersive spectrometer. The Wolter Type III has never been employed for X-ray astronomy (NASA Imagine the Universe!).

Named after Hans Wolter (1911-1978), a German physicist who designed the optical configuration.

Woltjer's theorem
  فربین ِ وُلتشر   
farbin-e Woltjer

Fr.: théorème de Woltjer   

In → magnetohydrodynamics, in the limit of zero → resistivity, the → magnetic field  B satisfies the → induction equation  ∂B/∂t = ∇ x (v x B), then for a → plasma confined by a perfectly conducting boundary, the → magnetic helicity is conserved. If the normal field is fixed on the boundary, the minimum-energy state is the linear → force-free magnetic field that conserves the total magnetic helicity.

Named after the Dutch astrophysicist Lodewijk Woltjer (1930-2019), who discovered the phenomenon in 1958 while studying the → Crab Nebula; → theorem.

<< < -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 > >>