An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) Deprived of life.
2) No longer producing or functioning. → dead pixel.

M.E. deed, O.E. dead "dead;" cf. O.S. dod, Dan. død, Swed. död, Du. dood, O.H.G. tot, Ger. tot; PIE *dhou-toz-, from base *dheu- "to die."

Mordé "dead," p.p. of mordan, mir- "to die," → death.

Of a → CCD detector, a pixel that is not sufficiently active.

→ dead; → pixel.

The time by which something must be finished or submitted; the latest time for finishing something (Dictionary.com).

Historically, during the American Civil War, the term referred to a physical line or boundary beyond which prisoners were shot; → dead; → line.

Ruzband, literally "day lock, that which blocks date," from ruz, → day, + band, → bond; cf. Ger. Stichtag, Anmeldeschluss, Einsendeschluss and Fr. date de clôture.

The act of dying; the end of life.

M.E. deeth, O.E. deað (cf. O.S. doth, O.Fris. dath, Du. dood, O.H.G. tod, Ger. Tod, O.N. dauði, Dan. død, Swed. död, Goth. dauþas "death"), from *dheu- "to die" + *-thuz "-th;"

Marg "death," from Mid.Pers. marg "death;" Av. mahrka- "death," mərəxš- "ruin;" related to Mod.Pers. mordan (present stem mir-) "to die;" Mid.Pers. murdan "to die;" O.Pers. mrt- "to die," amriyta "dies," martiya- "(mortal) man" (Mod.Pers. mard "man"); Av. mərəta- "died;" cf. Skt. mar- "to die," mrti- "death," marc- "to damage, hurt, injure;" PIE base *mor-/*mr- "to die." Cognates in other IE languages: Gk. emorten "died," ambrotos "immortal;" L. morior "I die," mortuus "dead" (Fr. mourir "to die," mort "dead"); Arm. merani- "to die;" O.C.S. mrutvu "dead;" O.Ir. marb; Welsh marw "died;" O.E. morþ "murder;" Lith. mirtis.

1a) A → discussion, as of a public question in an assembly, involving opposing viewpoints.
1b) A formal contest in which the affirmative and negative sides of a proposition are advocated by opposing speakers.
2) To engage in argument or discussion, as in a legislative or public assembly (Dictionary.com).

M.E. debaten, from O.Fr. debatre, literally "to fight," from → de- "down, completely," + batre "to beat," → beat.

Vâzat, from vâ-, → de-, + zat- (Baluci žat-) variant of zad-, zadan "to strike, beat", → beat.

To substract the → bias from a flat-field or science frame obtained using an electronic detector.

Debias, from → de- + → bias.

Varak zodudan, from varak→ bias + zodudan "to polish, clean," Mid.Pers. uzdātan, Av. uzdā-, from uz-, → ex-, + dā- "make, create."

The process of removing the → bias from a → flat-field or science → frame. → debias

Verbal noun of → debias.

In → spectroscopy, to → resolve a → blend into its constituent → spectral lines.

Deblend, from → de- + → blend.

Tuham, → blend, + zodudan "to polish, clean," Mid.Pers. uzdātan, Av. uzdā-, from uz-, → ex-, + dā- "make, create."

The process or state of separating or resolving into constituent → spectral lines.

Verbal noun of deblend, from → de- + → blend.

To → increase the → spatial resolution or the clearness of an → image. Same as → sharpen. See also → deconvolve.

Deblur, from → de- + → blur.

Tigidan "to sharpen," from tig "sharp," variants tiz, tež, tej, tij, tiq, Mid.Pers. tigr, têz, têž "sharp," O.Pers. tigra- "pointed," tigra.xauda- "pointed helmet (epithet of Scythians)," Av. tiγra- "pointed," tiγray- "arrow," tiži.arštay- "with the pointed spear," cf. Skt. tikta- "sharp, pungent, bitter," tejas- "sharpness, edge, point or top of a flame;" PIE base *st(e)ig- "to stick; pointed." Cognates in other IE languages: Gk. stizein "to prick, puncture," stigma "mark made by a pointed instrument," L. in-stigare "to goad," O.H.G. stehhan, Ger. stechen "to stab, prick," Du. stecken, O.E. sticca "rod, twig, spoon," E. stick.

The process or state of making an image sharper. → deblur; same as sharpening. → deconvolution.

Verbal noun of → deblur.

The remains of anything broken down or destroyed; rubble; ruins.
Astro.: → debris disk; → orbital debris.
Geology: An accumulation of loose fragments of rock.

From Fr. débris, from M.Fr. débriser "break down, crush," from O.Fr. debrisier, → de- + brisier "to break," from L.L. brisare.

Tifâl, from tif "rubbish, sweepings, debris" + -al relation suffix → -al.

A disk developing around a star after the dissipation of the → protoplanetary disk of gas and dust whose material was used in the formation of planets during the first 10 million years. The resulting debris disk is mainly composed of residual → planetesimals analogous to → asteroids, → comets, and → Kuiper Belt Objects in the Solar System. Their mutual collisions produce observable → dust emission in a belt encompassing the planetary system.

→ debris; → disk.

A → unit of electric → dipole moments, equal to 10^-18 → CGS units or 3.336 x 10^-30 → coulomb meter.

After Peter Joseph Wilhelm Debye (1884-1966), Dutch-born American, who made important studies in the conductivity of electricity by salt solutions and in the heat capacity of solids. He received the 1936 Nobel Prize in chemistry for his work on the structure of molecules.

The → Debye model at → low  → temperatures, where the → specific heat is proportional to the cube of the → absolute temperature, i.e. C_V ∝ T³.

→ debye; → law.

A characteristic length scale in a → plasma, determined by the temperature and number density of the charged particles. The Debye length (in cm) is given by the expression: λ_D = 743(T_e/n_e)^1/2, where T_e is the electron temperature in → electron-volts and n_e is the electron density in cm^-3. Particles which pass each other at distances smaller than the Debye length interact directly. Outside the Debye length particle interactions are dominated by collective effects. In typical laboratory plasmas the Debye length is small compared with the plasma dimension, so that collective effects are important.

→ debye (D); → length.

An extension of the → Einstein model accounting for → specific heats, based on the concept of → elastic waves in → crystals. In this model specific heat is given by: C_V = 9R[(4/x²)∫ y²/(e^y - 1)dy - x/(e^x - 1)], integrating from 0 to x, where R is the → gas constant, k is → Boltzmann's constant, x = hν_max/k, and y = hν/k. The parameter T_D = hν_max/k is the characteristic → Debye temperature of the crystal. At low temperatures the specific heat prediction by this model is in good agreement with observations (→ Debye law), in contrast to Einstein's model.

→ debye; → temperature.

The characteristic → temperature of the → crystal as given by the → Debye model of → specific heats.

→ debye; → temperature.

Prefix meaning "ten" and "ten times" used in terms belonging to the metric system.

From Fr. déca-, from L. deca-, dec-, from Gk. deka "ten;" cf. Av. dasa "ten," Mod.Pers. dah "ten," Skt. dasa, PIE *dekm (Dan. ti, Du. tien, Ger. zehn, E. ten, Fr. dix).

Dekâ-, from Fr. as above.

A ten-sided → polygon. A decagon that is equilateral and equiangular is called a regular decagon. Each angle of a regular decagon is 144°. The central angle subtending any side is 36°. The ratio of the radius to the side of a regular decagon forms the → golden ratio.

→ deca-; → -gon.