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

A distinctive name or title; appellation. → Bayer designation; → Flamsteed designation; → variable star designation.

From L. designatus, p.p. of designare "to mark out, choose, appoint," from → de- "out" + signare "to mark," from signum, → sign.

Nâmgozini, from nâm, → name, + gozini "choosing," from gozidan "to chose," → select.

The act of deciding definitely and firmly; the result of such an act of decision.

Verbal noun of → determine.

Instantaneous combustion or conversion of a solid, liquid, or gas into larger quantities of expanding gases accompanied by heat, shock, and a noise. → deflagration; → explosion.

Verbal noun of → detonate.

The difference between the deuterium (D)/hydrogen (H) → abundance → ratio in an object with respect to that representing a standard or mean value for that type of objects. Same as → isotope fractionation of deuterium. In the gas phase chemistry many of the D fractionation reactions produce an excess of D atoms relative to → hydrogen atoms. Deuterium fractionation in → interstellar cloud cores, → protostars, and → Solar System bodies is frequently used to infer important aspects of their physical and chemical histories. For example, the → deuterium enhancement in the Earth's sea water, with respect to the cosmic abundance, has been interpreted as being due to → enrichment by → comet-like → planetesimals colliding with the young Earth.

→ deuterium; → fractionation.

1) An act or instance of discriminating, or of making a distinction.
2) Unfair treatment of a person, racial group, minority, etc; action based on prejudice (Dictionary.com).

Verbal noun of → discriminate.

A process where a positive molecular ion recombines with an electron, and as a result it dissociates into two neutral products. For example, AB⁺ + e^-→ A + B, where e^- is an electron, AB⁺ is a diatomic or polyatomic molecular ion, and A and B are the neutral fragmentation products. Dissociative recombination is the dominant recombination process in planetary ionospheres and interstellar clouds.

→ dissociative; → recombination.

An act or instance of dominating.

Verbal noun of → dominate.

1) The act of eliminating; the state of being eliminated.
Math.: The process of solving a system of simultaneous → equations by using various techniques to remove the → variables successively (Dictionary.com).

Verbal noun of → eliminate; → -tion.

An act or instance of emanating; something that emanates or is emanated.

→ emanate; → -tion.

1) The act of examining; inspection; inquiry; investigation.
2) The state of being examined.
3) The act or process of testing pupils, candidates, etc., as by questions (Dictionary.com).

Noun from → examine.

1) The act or process of explaining.
2) A statement made to clarify something and make it understandable.

Verbal noun of → explain.

A stellar designation system in which each star is assigned a number followed by the Latin genitive of its corresponding → constellation, such as → 61 Cygni and 82 Eridani. Compare with the → Bayer designation.

Named after John Flamsteed (1646-1719), founder of the Greenwich Observatory, and the first astronomer royal of England, who introduced this system in his catalog Historia Coelestis Britannica (1725); → designation.

1) Any of various methods of separating the components of a mixture into fractions of different properties.
2) → isotope fractionation

Verbal noun from → fractionate.

A method of solving a matrix equation of the form A x = b, where A is a matrix and x and b are vectors. The process consists of two steps, first reducing the elements below the diagonal to 0 and second, back substituting to find the solutions.

→ Gaussian; → elimination.

The process of combining or exposing to → hydrogen.

General: An act or instance of illuminating. The fact or condition of being illuminated.

Illumination, from O.Fr. illumination, from L. illuminationem (nom. illuminatio), from illuminare "to throw into light," from → in- "in" + lumen "light," cognate with Pers. rowšan, as below.

Rowšanâyi, noun of quality and state from rowšan "bright, clear," related to ruz "day," foruq "light," and afruxtan "to light, kindle," rowzané "window, aperture;" Mid.Pers. rôšn "light; bright, luminous," rôc "day," rocânak "window;" O.Pers. raucah-, Av. raocana- "bright, shining, radiant," raocah- "light, luminous; daylight;" akin to Skt. rocaná- "bright, shining," roka- "brightness, light;" Gk. leukos "white, clear;" L. lux "light," also lumen "light, window," luna "Moon;" E. light; Ger. Licht; Fr. lumière; PIE base *leuk- "light, brightness."

1) The faculty of imagining, or of forming mental images or concepts of what is not actually present to the senses.
2) The action or process of forming such images or concepts (Dictionary.com).

→ imagine; → -tion.

1) The angle between two lines or two planes.
2) An orbital element that defines the angle between the orbital plane of a solar system body (planet, comet, asteroid) and the plane of the ecliptic.
3) The angle between the equatorial and orbital planes of a planet.

Inclination, from M.E. inclinacioun, from L. inclination-, from inclinat(us) p.p. of inclinare, from → in- + clinare "to bend;" cf. Gk. klinein "to cause to slope, slant, incline;" Skt. sri- "to lean," O.Pers. θray-; Av. sray- "to lean;" Mod.Pers. kil "bent, inclined, slant;" PIE base *klei- "to lean, incline" from which is also derived P.Gmc. *khlinen (Ger. lehnen, E. lean).

Darkil, from prefix dar- "in" + kil "bent, crooked, inclined" [Dehxodâ], Mid.Pers. xwahl "bent, crooked" (Mod.Pers. dialectal/colloquial variants kowleh, cowleh, cowl, caval, xohl, xohal, hol), cf. Skt. kûla- "slope, declivity;" PIE base *klei-, as above.

The angle between the rotation axis of a planet and the normal to the ecliptic.

→ inclination; → axis.

→ obliquity of the ecliptic.

→ inclination; → Earth; → equator.