Fr.: luminosité de vent
The final kinetic energy of the → stellar wind expressed by: (1/2)Mdot.v∞2 = (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.
Fr.: moment angulaire de vent
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.
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."
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.
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.
1) Anything likened to a window in appearance or function.
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; forusorx→ infrarouge.
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.
mey (#), bâdé (#), nabid (#)
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
1) Either of the two limbs of a bird allowing her to fly.
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."
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.
M.E., OE; cf. O.Fris., Du. winter, O.S., O.H.G. wintar, Ger. winter, Dan., Swed. vinter, Goth. wintrus "winter"),
Zemestân "winter," related to zam "cold," Mid.Pers. zam, zamistân "winter;" Av. zimô "winter;" cf. Skt. hima- "cold, frost;" Ossetic zymæg/zumæg "winter;" Gk. xeimon "winter;" L. hiems "winter;" Lith. ziema "winter;" PIE *gheim- "snow, winter."
Fr.: solstice d'hiver
The moment in the northern hemisphere when the → Sun attains its lowest → declination of -23°26' (or -23°.44) with respect the → equator plane. It happens when the Earth's axis is orientated directly away from the Sun, on 21 or 22 December. During the northern winter solstice the Sun appears to be directly overhead at noon for places situated at → latitude 23.44 degrees south, known as the → tropic of Capricorn. The winter solstice can occur at any moment during the day. Two successive winter solstices are shifted in time by about 6 h. The winter solstice in the northern hemisphere is the → summer solstice in the southern hemisphere.
A slender flexible thread or rod of metal.
M.E., O.E. wir, cf. O.N. viravirka "filigree work," Swed. vira "to twist," O.H.G. wiara "fine gold work."
Sim "wire," initially "strand of silver," from sim "silver," from Mid.Pers. asêm "silver," from Gk. asemon "without mark, uncoined, shapeless, formless," from argurion asemon "uncoined money." For semantic similarity, see → silver.
The quality or state of being → wise; knowledge of what is true or right coupled with just judgment as to action; sagacity, discernment, or insight (Dictionary.com). Wisdom is gained over the years through experience. It is the insight in knowing the probable outcome learned through experience. In contrast, → reason is using the → rational → reasoning to evaluate pros and cons in making a decision.
Xerad "understanding, judjement, intellect, wisdom;" Mid.Pers. xrad "reason, intellect, intelligence, wisdom, understanding;" O.Pers. xraθu- "wisdom;" Av. xratu- "intelligence, understanding, wisdom; will, purpose, council;" cf. Skt. krátu- "power, will-power;" Gk. kratos "power, strength."
Having the power of discerning and judging properly as to what is true or right; possessing discernment, judgment, or discretion (Dictionary.com).
From M.E. wis, wys, from O.E. wis ("wise"), cognate with Du. wijs, Ger. weise, Norw. and Swed. vis.
Xeradmand, from xerad, → wisdom, + -mand relatrion and possession suffix.
Fr.: Wolf-Rayet WN
A → Wolf-Rayet star whose spectrum is dominated by emission lines of ionized nitrogen: N II 3995 Å, N III 4634-4661 Å, N III 5314 Å, N IV 3479-3484 Å, N IV 4058 Å, N V 4603 Å, N V 4619 Å, and N V 4933-4944 Å. This type is divided in sub-types WN2 to WN11.
Fr.: étoile WN/WC
An object showing signatures of both → WN Wolf-Rayet stars and → WC Wolf-Rayet stars in the same spectrum, originating from individual stars rather than from WN + WC → binary systems. Such a WN/WC signature implies that the surface composition of the star is → nitrogen and → carbon enriched. This hybrid state results from a mixing process between He-burning → convective core and the overlying nitrogen enriched layers. According to model predictions, this situation corresponds to a short transition phase, lasting 103 to 104 years, during which a WN star evolves into a WC star. The WN/WC stars so far detected are all of early types.
Fr.: étoile WN10
Fr.: étoile WN11
A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N II 3995 Å as strong as He II 4686 Å, N III 4634-4641, 5314 Å weak or absent, Balmer lines, He I with → P Cygni profile.