An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 902
affine combination
  میازش ِ کروَن   
miyâzeš-e karvan

Fr.: combinaison affine   

A linear combination of vectors in which all the vector coefficients add up to one.

affine; → combination.

affine geometry
  هندسه‌ی ِ کروَن   
hendese-ye karvan

Fr.: géométrie affine   

The study of the properties which are → invariant under → affine transformations.

affine; → geometry.

affine set
  هنگرد ِ کروَن   
hangard-e karvan

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.

affine; → set.

affine transformation
  ترادیس ِ کروَن   
tarâdis-e karvan

Fr.: transformation affine   

Any → transformation preserving → collinearity.

affine; → transformation.


Fr.: affinité   

1) General: A relationship or resemblance.
2) Math.: The state, quality, or fact of being → affine.

affine; → -ity.

vand (#)

Fr.: affixe   

A linguistic element added to a word or root to produce a derived or inflected form. General term for → infix, → prefix, → suffix, and → circumfix.

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.

  اکانون، بی‌کانون   
akânun, bikânun (#)

Fr.: afocal   

Describing a lens or optical system with a convergent power of zero, whose object and image points stretch to infinity. Thus, → afocal system.

Afocal, from → a- + → focal.

Akânun, from a- negation prefix, → a- + kânun, → focus. Bikânun, from bi- negation prefix + kânun, → focus.

afocal system
  راژمان ِ اکانون   
râžmân-e akânun

Fr.: système afocal   

An optical system with object and image points at infinity.

afocal; → system.

  پس، پسان   
pas, pasân (#)

Fr.: après   

1) Behind in place or position; following behind.
2) Later in time than; in succession to; at the close of (

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.
2) Lingering → radiation that remains after a violent → event such as a → gamma-ray burst. The afterglow of any gamma-ray burst is caused by an event different from the original explosion, likely by → shock waves colliding with the ambient medium. Afterglows occur in a large range of → electromagnetic  → wavelengths.

after; → glow.


Fr.: après, ensuite, plus tard   

At a later or subsequent time; subsequently.

after; → -ward.

AG Carinae
   AG افزل   
AG Afzal

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).

AG, as used in the → variable star designation system; → Carina.

  دوباره، باز   
dobâré, bâz

Fr.: encore   

Once more; a second time; in return.

M.E., from O.E. ongean "toward, opposite, against," from on "on" + -gegn "against, toward."

Dobâré, from do, → two, + bâr "time, fold," → twice.


Fr.: contre   

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)
  تپه‌ی ِ گرمایی ِ پایانی ِ AGB   
tape-ye garmâyi-ye pâyâni-ye AGB

Fr.: flash de l'hélium final de l'AGB   

In evolutionary models of → low-mass and → intermediate-mass stars, the occurrence of a → helium shell flash just at the moment when the star is leaving the → asymptotic giant branch phase.

AGB; → final; → thermal; → pulse.

  ۱) سن؛ ۲) عصر   
1) senn (#); 2) asr (#)

Fr.: âge   

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.
2) a: A period of time in the history of the Universe marked by a distinctive characteristic. → cosmic dark age. b: A division of geologic time in the history of the Earth, usually shorter than an epoch.

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
  ۱) کهن‌روزی ِ ماه؛ ۲) سن ِ ماه   
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
  سن ِ گیتی   
senn-e giti

Fr.: âge de l'Univers   

The time elapsed since the → Big Bang.

age; → universe.

Agena (β Centauri)

Fr.: Agena   

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.

konešgar (#)

Fr.: agent   

1) Something such as a chemical substance, organism, or natural force that causes an effect.
2) Somebody who provides a particular service for another.

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.

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