<< < -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 > >>
Of or pertaining to a → vortex.
Adj. from → vortex.
In fluid mechanics, a measure of the rate of rotational spin in a fluid.
Mathematically, vorticity is a vector field defined as the curl of the velocity field:
ω = ∇ x v.
A speech sound that is produced as a stream of air that is not obstructed or blocked in any way by the vocal organs, but only modulated by the position of the tongue, lips, etc.
A hypothetical small planet proposed in the 19-th century to exist in an orbit between Mercury and the Sun. In order to explain some characteristics of Mercury's orbit, the French astronomer Urbain Jean Joseph Le Verrier (1811-1877) hypothesized the presence of another planet, which he named Vulcan. Those particularities of Mercury's orbit were later explained by Albert Einstein's theory of general relativity.
L. Vulcanus in Roman mythology the blacksmith god of fire and volcanoes, a word of Etruscan origin
1) Characterized by ignorance of or lack of good breeding or taste.
From L. vulgaris, volgaris "of or pertaining to the common people, common, vulgar, low, mean," from vulgus "the common people, multitude, crowd, throng" (cognates: Skt. varga- "a company, group, section," Pers. jarga, as below, Gk. eilein "to press, throng," Welsh gwala "sufficiency, enough").
Jargvâr, from jarg, jarga, jargé "a group of people, a ring of men or beasts;" cf. Lori, Laki jarga "group, throng," jarra "bundle;" Kurd. jerge, cerge "assembly, club;" + -vâr a suffix denoting "suiting, befitting, resembling, in the manner of, possession."
Fr.: fraction d'entiers
Same as → common fraction.
M.E., from L. vulgaris, from vulgus "the common people," + -aris, → -ar.
Fr.: Petit Renard
The Little Fox. A faint constellation in the northern hemisphere, at 20h right ascension, +25° declination, between Cygnus and Aquila. Abbreviation: Vul; Genitive: Vulpeculae.
L. Vulpecua, from vulpes "fox," cognate with Pers. rubâh, as below, + diminutive suffix -cula, variant of → -ule.
Rubâhak "little fox," from rubâh
VY Canis Majoris (VY CMa)
VY Sag-e Bozorg
Fr.: VY Grand Chien
A → red supergiant star which is one of the largest and most intrinsically luminous stars in the sky. It has a radius of about 1,420 solar radii (→ solar radius) and a luminosity of 3 × 105 Lsun (→ solar luminosity). It is about 3,900 → light-years from the Earth. Excluding solar system bodies, VY CMa is the third brightest object in the sky at 10 µm. It has a large optical → reflection nebula, visible through even small telescopes, created by its prodigious mass loss (> 10-4 Msun per year). Its initial mass is estimated to be about 25 Msun and its current mass 17 Msun. Recent observations have shown the presence of submicron → dust grains, with an average radius of ~ 0.5 μm, in the ejecta. These grains are 50 times larger than those found in the diffuse → interstellar medium (P. Scicluna et al., 2015, A&A, 584L, 10S).
Fr.: étoile de type Vz
A class of → O-type stars whose spectra show He II 4686 absorption line much stronger than any other He line especially He II 4541 or He I 4471. Vz stars are thought to be young stars lying close to the → ZAMS (Walborn & Parker 1992, ApJ 399, L87). Alternatively, the Vz characteristics may be related to the wind properties rather than to the youth of the star (Martins et al., 2005, A&A 441, 735).
Fr.: W 43
One of the most massive → star formation regions in the → Galaxy, situated in the constellation → Aquila at the junction point of the → Galactic bar and the → spiral arms. It lies at a distance of about 6 kpc from the Sun and covers a vast area of the → Galactic plane with l = (29° to 32°) and b = (-1° to + 1°). W 43 is a complex of more than 20 → molecular clouds in 13CO emission with systemic velocities ranging from 12 km s-1 to 110 km s-1. The total → virial mass is estimated to be several 106Msun. Close to its center, W 43-Main is undergoing a remarkably efficient episode of → star formation and qualifies as a mini-starburst Among the 15 dense cores of W 43-Main (0.2 pc FWHM size and 5 × 105 cm-3 density), three extremely massive, → dense cores are potentially forming → massive stars: W 43-MM1 (M = 3600 Msun), W 43-MM2 (M = 1600 Msun), and W 43-MM3 (M = 1000 Msun). Adjacent to W 43-Main is a → giant H II region, illuminated by a cluster of → Wolf-Rayet and → OB stars, emitting ~ 1051 → Lyman continuum photons per second and a → far-infrared → continuum luminosity of ~ 3.5 × 106 Lsun. It is not yet clear what the impact is of this → starburst cluster on the W 43-Main cloud located 2-10 pc away. With its special characteristics, W 43 represents a type of molecular cloud complex which hosts high luminosity embedded clusters. Other well-known examples are W 49 and W 51 (e.g., Nguyen Luong et., 2013, arXiv:1306.0547).
Number 43 in the following catalog: Gart Westerhout, 1958, Bull. Astron. Inst. Netherlands, 14, 215, A survey of the continuous radiation from the galactic system at a frequency of 1390 Mc/s.
Fr.: boson W
A → boson particle that, along with → Z boson, mediates the → weak force in particle interactions. Two kinds of W bosons exist, the W+ and its antiparticle W-. With a mass of 80.4 GeV/c2, the W boson is almost 100 times as massive as the → proton.
W Virginis star
setâre-ye W dušizé
Fr.: étoile de type W Virginis
A member of a class of → pulsating stars with a period of 1 to 35 days located in the → instability strip of the → H-R diagram. Also known as type II Cepheid variables, W Virginis stars are typically 1.5 mag fainter than classical Type I Cepheids and have a mass less than that of the Sun. They also exhibit a period-luminosity relation which is distinct, but works in a similar way to the relation for Type I Cepheids. Hence W Virginis stars can also be used to measure Galactic and extragalactic distances.
Short for → Wolf-Rayet.
setâre-ye W-R (#)
Fr.: étoile W-R
Short for → Wolf-Rayet star.
The most luminous → galaxy known. It has a → redshift of z = 4.601 and a → bolometric luminosity of 3.5 × 1014Lsun. W2246-0526 hosts a deeply buried → active galactic nucleus (AGN)/→ supermassive black hole (SMBH). Discovered using the → Wide-field Infrared Survey Explorer (WISE), W2246-0526 is classified as a → hot dust-obscured galaxy, based on its → luminosity and → dust temperature (T. Diaz-Santos et al. 2015, arXiv:1511.04079).
Object designation from → Wide-field Infrared Survey Explorer (WISE).
To walk through water, snow, sand, or any other substance that impedes free motion or offers resistance to movement (Dictionary.com).
M.E. waden "to go, wade;" O.E. wadan "to go;" cf. Dan. vade, O.Fris. wada, Du. waden, Ger. waten, O.Norse vatha; akin to O.E. wæd "ford, sea," L. vadere "to go, rush," vadum "shoal, ford."
Gampidan, related to Proto-Ir. *gamp-, *gamb- "to move," cf. Dezfuli gomba, Bardesiri gopak "jump with two feet;" Sogd. (+ *â-) âγamp "walking;" (+ *uz-) Yighda žib-/žibi- "to rise, to stand," jib- "to awake;" (+ *ham-) Wakhi gəfs-/gəfst- "to run."
1) The track left by a moving ship.
Cognate with M.L.G. wake "wake," Nor. dialect vok, O.N. vok, voka "hole in the ice."
Kel, from Tabari kel, kal "trail, track, footprint."
1) camidan (#), gâmidan (#); 2) cam; puyeš (#)
Fr.: 1) marcher; 2) marche
M.E. walken, from O.E. wealcan "to toss, roll;" cf. O.N. valka "to drag about," Dan. valke "to full," M.Du. walken "to knead, press, full," O.H.G. walchan "to knead," Ger. walken "to full."
Camidan "to walk (proudly)," variant gâmidan "to walk,"
gâm "step, pace" (related to âmadan "to come,"
Mid.Pers. gâm "step, stride, pace;"
O.Pers. gam- "to come; to go;" Av. gam- "to come; to go,"
jamaiti "goes;" cf. Skt. gamati "goes;"
Gk. bainein "to go, walk, step;" L. venire "to come;"
Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come;
PIE stem *gwem- "to go, come."
1) An upright continuous structure that divides one
area from another or surrounds an area.
M.E., from O.E. w(e)all "rampart, dike, cliff," also "defensive fortification around a city, side of a building" (O.Sax., O.Fris., M.L., M.Du. wal), from L. vallum "wall, rampart."
Divâr "wall," from Mid.Pers. dîvâr "wall;" related to Mid.Pers. bâr, var "enclosure, defences, fortress;" Mod.Pers. bâru "wall, rampart, fortification; fort; tower;" O.Pers. didā- "wall, stronghold, fortress;" Av. var- "castle," from var- "to cover, conceil;" Proto-Iranian *dida-vāra-; cf. Skt. dehī- "wall;" Gk. teikhos "wall;" E. dike, ditch.
Fr.: photométrie de Walraven
A photometric system with five wavelength ranges that does not use filters. Instead it uses prisms and lenses (spectroscopy) to select the bands simultaneously. The wavelengths and the bandwidths are: W, 3250 and 140 Å; U, 3630 and 240 Å; L, 3840 and 230 Å; B, 4320 and 450 Å; and V, 5470 and 720 Å. The Walraven photometer was unique in design and remained literally unique as copies were never built. In addition, during its whole life the photometer was mounted permanently on the same telescope that had been built specifically for this instrument, the 91 cm Lightcollector' reflector, which started in 1958 at the Leiden Southern Station in Broederstroom, South-Africa. After 20 years in South-Africa the telescope and photometer were moved to the European Southern Observatory La Silla observatory in Chile. The photometric observations were resumed in March 1979 and continued for another 12 years until the decommissioning of the photometer in 1991.
After the inventors, the Dutch astronomer Theodore Walraven (1916-) and his wife Johanna Helena Walraven, née Terlinden (1920-89); → photometry.