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

A person who is present at a specific time or place.

From → attend + suffix -ee

Âtângar agent noun from → attend; pârgertandé agent noun from pârgertidan, → participate.

1) The act or faculty of attending, especially by directing the mind to an object.
2) Observant care; consideration (Dictionary.com).

→ attend; → -tion.

1) Characterized by or giving attention; observant.
2) Thoughtful of others; considerate; polite; courteous (Dictionary.com).

→ attend; → -ive.

1) To reduce in force, value, amount, or degree. → attenuation, → attenuation factor.
2) To reduce the amplitude of an electrical signal with little or no distortion.

L. attenuatus, p.p. of attenuare "to make thin," from → ad- "to" + tenuare "make thin," from tenuis "thin;" cf. Gk. tanaos "thin, slender, elongated;" Skt. tanuka-, tanu- "thin;" Av. tan- "to stretch;" Pers. tonok "thin," as below; O.Ir. tanae "delicate, thin;" O.H.G. dunni "thin."

Tonokidan, from tonok "thin, slender, slight, tender, delicate" + -idan, infinitive suffix. Tonok, from Mid.Pers. tanuk, Av. root tan- "to stretch, extend," cognate with L. tenuis, as above.

The falling off of the energy density of radiation with distance from the source, or with passage through an absorbing or scattering medium.

Verbal noun of → attenuate.

The fraction of a beam of → X-rays or → gamma rays that is absorbed or scattered per unit thickness of the → absorber. The linear attenuation coefficient, denoted by the symbol μ, appears in the equation I(x) = I₀e^-μx, where I(x) is the intensity at depth of x cm and I₀ is the original intensity.

→ attenuation; → coefficient.

The ratio of the radiation intensity after traversing a layer of matter to its intensity before.

→ attenuation; → factor.

Position of a satellite with respect to the horizon or some other fixed reference plane.

Fr., from It. attitudine "disposition, posture," from L.L. aptitudo "faculty."

Ruykard, noun from ruy kardan "to turn the face toward," from ruy "face" (Mid.Pers. rôy, rôdh "face," Av. raoδa- "growth," in plural "appearance," from raod- "to grow, sprout, shoot," cf. Skt. róha- "rising, height") + kardan "to do, make, perform" (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 k^wer- "to do, to make").

→ position.

A prefix meaning 10^-18.

From Danish or Norwegian atten "eighteen," from O.N. attjan "eighteen," from atta "eight" (compare with Gk. okto, L. octo, Skt. astau, Av. ašta-, Mod.Pers. hašt; PIE *okt(u)) + tjan "ten" (compare with Skt. dasa, Av. dasa, Mod.Pers. dah, Gk. deka, L. decem; PIE *dekm).

To cause to draw near or adhere by physical force.

L. attractus, p.p. of attrahere "to draw, to attract," from ad- "to" + trahere "to pull, draw."

Darkašidan, from dar- "in, into" + kašidan "to draw, attract," → galaxy.

The act or capability of attracting. A physical force (gravitational, electric, magnetic, etc.) exerted by material bodies.

Attraction, n. from → attract.

Having the quality of attracting.

Verbal adj. from → attract.

A physical force (→ gravitational, → electric, → magnetic, etc.) by which a body attracts another.

→ attractive; → force.

The physical body that attracts. → Great Attractor.

→ attract; → -or.

1) General: Something attributed as belonging to a person, thing, or group; a quality, characteristic, or property.
2) Computer science: A characteristic that describes an → entity.
3) To explain as resulting from a specified cause; to regard as caused by something indicated.

M.E., from L. attributus, p.p. of attribuere "to assign to, add, bestow;" figuratively "to attribute, ascribe, impute," from → ad- "to" + tribuere "to pay, assign, give, bestow," → distribute.

Âbâž, âbâžé, from â- strength or nuance prefix + bâž "tribute, toll, impost," → distribute.

1) The act of attributing.
2) Something attributed.

Verbal noun of → attribute.

A type of → achondrite meteorite composed mostly of the magnesium silicate mineral → enstatite (Mg₂Si₂O₆). The group is named for the small Aubres → meteorite that fell near Nyons, France, on Sep. 14, 1836. Outside Antarctica only about 10 aubrites are known, mostly the result of witnessed falls. Aubrites make up only 0.14% of all known meteorites in our terrestrial meteorite collection.

From Fr. Aubres, a commune in the Drôme department in southeastern France; + → -ite.

An electron that is emitted when an electron from a higher → energy level falls into a → vacancy in an inner shell, according to the → Auger-Meitner effect. The process usually occurs when the atom is bombarded with high energy electrons. If the collision ejects an inner-shell electron, an electron from a higher level will quickly drop to this lower level to fill the vacancy. Most of the time, the energy is released in the form of a photon. But sometimes the energy is transferred to another electron, which is ejected from the atom.

→ Auger-Meitner effect; → electron.

The → emission of an → electron when an → atom transits to a less → excited state. More specifically, → ionization of an atom by a very energetic photon can bring about the ejection of an inner electron of the atom. Consequently, the atom becomes unstable and rapidly undergoes a → spontaneous transition. As a result, an outer electron moves inward and fills the → vacancy produced in the inner orbit. Energy conservation requires that this transition be accompanied by the emission of a photon or a peripheral electron. The latter is called the → Auger electron. Knowing the electron energy leads us to characterize the atom from which it was ejected. This effect is used, in the Auger spectroscopy, to analyze the surface compositions of materials.

This effect was discovered in 1923 Lise Meitner (1878-1968) and in 1925 independently by Pierre Auger (1899-1993).

The Charioteer. A conspicuous northern constellation lying midway between → Perseus and → Ursa Major and in a region crossed by the → Milky Way. The brightest star is → Capella. Auriga is the site of the Galactic → anticenter. Abbreviation: Aur; genitive form: Aurigae.

L. auriga "a charioteer, driver," from aureæ "bridle of a horse" + agere "set in motion, drive, lead."

Arrâberân "charioteer," from arrâbé "chariot, cart" + rân "driver," from rândan "to drive." Arrâbé probably from *arâba, from *râba, from *râda, compare with Av. ratha- "chariot," akin to Skt. rathah "car, chariot," L. rota "wheel," rotare "revolve, roll," Lith. ratas "wheel," O.H.G. rad, Ger. Rad, Du. rad, O.Ir. roth; PIE *roto- "to run, to turn, to roll."
Gardunerân "a charioteer," from garduné "chariot, car," from gardun "wheel; heaven," from gardidan "to turn, revolve."