Fr.: combinaison affine
A linear combination of vectors in which all the vector coefficients add up to one.
Fr.: géométrie affine
Fr.: ensemble affine
A set → if and only if (iff) for any two points in the → set, the line through them is contained in the set. In other words, for any two points in the set, their → affine combinations are in the set itself.
Fr.: transformation affine
1) General: A relationship or resemblance.
From L. affixus "fastened to," p.p. of affigere "fasten to, attach," from af-, variant of → ad- "to" + figere "fasten."
Vand, variant band "tie, band," present stem of Mod.-Mid./Pers. bastan/vastan "to bind, shut;" Av./O.Pers. band- "to bind, fetter," banda- "band, tie;" cf. Skt. bandh- "to bind, tie, fasten;" PIE *bhendh- "to bind," cf. Ger. binden, E. bind.
akânun, bikânun (#)
Describing a lens or optical system with a convergent power of zero, whose object and image points stretch to infinity. Thus, → afocal system.
Fr.: système afocal
An optical system with object and image points at infinity.
→ afocal; → system.
pas, pasân (#)
1) Behind in place or position; following behind.
M.E., from O.E. æfter "after, next, following in time," from O.E. of "off," cf. apo- + -ter a comparative suffix.
Pas "after," → back-; pasân with place/time suffix -ân.
1) A broad glowing arc of radiance, sometimes seen high in the
western sky at → twilight,
caused by the → scattering effect of
→ fine dust particles
suspended in the → upper atmosphere.
Fr.: après, ensuite, plus tard
At a later or subsequent time; subsequently.
Fr.: AG de la Carène
A → Luminous Blue Variable star in the constellation → Carina; also known as HD 94910. AG Carinae lies about 6 kpc (20,000 → light-years) away and is surrounded by a → nebula. It is also a → spectroscopic variable, with the variability on time-scale of years. During the epochs of minimum in the visual → light curve (mV ~ 8.1), the star is relatively hot and has a → WN11 spectral type, showing strong He I, H I, and N II → emission lines, weak He II 4686 Å emission, and Si IV 4088-4116 Å absorption. During the maximum epochs of the light curve (mV ~ 6.0), the star is cooler, and the spectrum is reminiscent of extreme A-type → hypergiants, with a strong emission of H I, Fe II, and T III lines. The transition between both phases is characterized by the appearance of peculiar features in the spectrum, such as absorption-line splitting, strong → electron-scattering wings in He I and Fe II lines, and apparent → inverse P Cygni profiles in He I lines. The presence of a massive → bipolar nebula around AG Car testifies to a recent (t< 104 years) phase of high → mass loss. The morphology and kinematics of the nebula suggest a → dynamical age of 8.5 × 103 years and a high mass of → ionized nebular material (~ 4.2 Msun), which is likely composed of → ejecta from the central star. The nebular abundances show evidence of moderate nitrogen → enrichment. Properties of the → circumstellar nebula, studied in the → mid-infrared and → far-infrared, reveal an incredibly high dust mass of ~ 0.25 Msun, → dust temperature between 76 and 99 K, and the presence of large → dust grains of ~ 1 μm, as deduced from far-→ infrared excess. Assuming a normal → gas-to-dust ratio of 100, the total nebular mass of AG Car could be as high as ~ 30 Msun which would be of the order of, or even higher than, the mass of the → Homunculus nebula around → Eta Carinae. At the time when the AG Car nebula was ejected, the → interstellar bubble around the central star likely contained a negligible amount of material compared to the total mass of the nebula, implying that most of the nebular mass was ejected by the central star (Groh et al., 2009, ApJ 698, 1698).
Once more; a second time; in return.
M.E., from O.E. ongean "toward, opposite, against," from on "on" + -gegn "against, toward."
In opposition to; contrary to; adverse or hostile to.
M.E. agens, ageynes, from ageyn, ongean "again," from on + gegn "against, toward," → gegenschein.
Patâr from Mid.Pers. paitiyârak, "every thing that counteracts and checks the good powers: adversaries of the evil powers;" Av. paiti-ār- "to advance against," paiti-ārəna- "adversary," from paiti- "against," → counter-, + ar- "to move," → access; cf. Mod.Pers. patyâré "affliction, misery, misfortune; anything ugly, terrific;" Mid.Pers. padirag, patirak "against, counter-," Sogd. patrêt "against, opposite, toward."
AGB final thermal pulse (AFTP)
tape-ye garmâyi-ye pâyâni-ye AGB
Fr.: flash de l'hélium final de l'AGB
1) senn (#); 2) asr (#)
1) The length of time that a celestial body or an evolutionary
stage of it has existed, i.e. the age of a
massive star, the age of a galaxy, a stellar cluster, and so on.
From O.Fr. aage, from Vulgar L. *ætaticum, from L. ætatem "period of life," from ævum "lifetime, eternity, age;" cf. Mid.Pers. awâm, âwâm "time, season," Av. âyav- "duration, period, time of life," Skt. âyuh- "life, health". All from PIE *aiw-, *ayu- "vital force, life, long life, eternity."
Senn from Ar. senn "age, lifetime". Asr from Ar.
age of the Moon
1) kohan-ruzi-ye mâh; 2) senn-e mâh
Fr.: âge de la lune
Same as → Moon's age.
→ Moon's age.
age of the Universe
Fr.: âge de l'Univers
The time elapsed since the → Big Bang.
Agena (β Centauri)
Alternative name for the star Hadar, the second brightest star in Centaurus and the tenth brightest star in the sky. → Hadar.
The etymology of Agena is not clear. Some sources have suggested L. a genu "by the knee," but it seems dubious.
1) Something such as a chemical substance, organism, or natural force that causes an effect.
From L. agentem (nominative agens, genitive agentis), pr.p. of agere "to set in motion, drive, lead, conduct," → act.
Konešgar, from koneš verbal noun of kardan "to do, to make" (Mid.Pers. kardan, O.Pers./Av. kar- "to do, make, build," Av. kərənaoiti "makes," cf. Skt. kr- "to do, to make," krnoti "makes," karma "act, deed;" PIE base kwer- "to do, to make") + -gar, → -or.