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

A form of → Hertzsprung-Russell diagram in which the luminosity is the vertical axis and the → color index the horizontal axis.

→ color; → luminosity, → diagram.

A form of → Hertzsprung-Russell diagram in which the visual absolute magnitude M_v is the vertical axis and the → color index the horizontal axis.

→ color; → magnitude, → diagram.

The measurement and definition of unknown colors in terms of standard colors.

→ color; → -metry.

The Dove. A small → constellation in the Southern Hemisphere just south to → Canis Major and → Lepus. Abbreviation: Col; genitive: Columbae.

L. columba "dove."

Kabutar "pigeon," Mid.Pers. kabôtar, from kabôd "grey-blue; pigeon," cf. Skt. kapota- "a dove, pigeon; the grey color of a pigeon."

CCD detector: Series of pixels arranged under one another.

Column, from O.Fr. columpne, from L. columna "pillar," collateral form of columen "top, summit," from PIE *kel- "to project."

Sotun, from Mid.Pers. stun, from O.Pers. stênâ "column," Av. stuna-, Skt. sthuna- "column."

Density of the interstellar matter lying between an object and the Earth in a cylinder with a unity base.

→ column; → density.

Either of two great circles of the celestial sphere that passes through the poles and meets the ecliptic at either the solstice points (the solstitial colure) or the equinox points (the equinoctial colure).

From L. colurus, from Gk. kolouros "dock-tailed," from kol(os) "docked" + -ouros "-tailed," from oura "tail;" so called because the lower part is permanently hidden beneath the horizon.

Koldom, from Mod.Pers. kol "docked, short," most probably cognate with the Gk. term, as above, + dom(b) "tail," Av. duma- "tail." Recorded in classical dictionaries, kol has several variants in a large number of dialects: kola, kalta, kel, kelma, koc, kall, kor, kul in Gilaki, Tâleši, Lori, Malâyeri, Hamedâni, Qâeni, and others, cf. Av. kaurva- "bald, docked," kaurvôduma- "with a bald tail," kaurvôgaoša- "with bald ears."

Prefix denoting "together; with; joint; jointly". It is sometimes used for intensification as in complete, complain, convince.

M.E., from O.L., classical L. form cum "together, together with," Gk. koinos "common," from PIE *kom- "beside, near, by, with."

Ham- and ham "together, with; same, equally, even," Mid.Pers. ham-, like L. com- and Gk. syn- with neither of which it is cognate. O.Pers./Av. ham-, Skt. sam-, sa-; also O.Pers./Av. hama- "one and the same," Skt. sama-, Gk. homos-; originally identical with PIE numeral *sam- "one," from *som-. The Av. hąm- (nasal a) appears in various forms: ham-, han- (before gutturals, palatals, dentals) and also həm-, hən-, ha- (Bartholomae, 1772). Variants in Pers. ha- as in (Anâraki) ha-bend, → connect, and (Kurd.) hasûn "to whet, sharpen," and hâ- as in hâ-dâdan, hâ-gereftan, see Dehxodâ.

1) The glowing envelope of gas and dust that surrounds a comet's nucleus.
2) An elongated, → comet-shaped → image of a → point source of → light caused by → aberration in the → optical system. In → telescopes it is often because → off-axis rays of light striking different parts of the → objective do not focus in the same → image plane.
→ Coma Berenices; → Coma cluster; → hydrogen coma.

L. coma "hair," from Gk. kome "hair;" → hair.

Berenice's Hair. A → constellation made up of many faint stars and located near the north Galactic pole between → Canes Venatici to the north, → Virgo to the south, → Leo to the west, and → Boötes to the east. Abbreviation: Com; genitive: Comae Berenices.

→ coma; L. Berenices genitive of Berenice, a queen of Egypt, wife of Ptolemy III, who sacrificed her hair to Aphrodite, begging her husband's victory in the war with the Assyrians, who had killed his sister. While the story is an old one, the constellation is relatively new, being introduced by Tycho Brahe (1546-1601).

The nearest rich cluster of galaxies which contains more than a thousand known galaxies, is about 20 million light-years in diameter, and lies about 280 million light-years away in the → constellation  → Coma Berenices. Also known as Abell 1656.

→ coma; → cluster.

1) General: The act of combining or the state of being combined.
2) Math: The number of ways elements making up a set can be arranged into various groups without regard to their order in the group. → permutation

Noun from → combine

A branch of mathematics dealing with the → combination and → permutation of sets of elements and mathematical relations that characterize their properties.

From combinator(ial) (from combinatorial analysis), + → -ics.

Miyâzešik, from miyâzeš, → combination, + -k, → -ics.

To cause to join in a close union or whole; unite.

From M.Fr. combiner, from L.L. combinare "to unite, yoke together," from L. → com- "together" + bini "two by two," adv. from bi- "two, twice," cf. Av. biš "twice," bi-, dva- "two," Skt. dvi- "two," Gk. di-, O.E. twi-.

Miyâzidan, infinitive from miyâz-, variant of miz- in â-miz-, âmixtan "to mix," âmizé, âmižé "mixture," âmiq "mixture; copulation;" Mid.Pers. âmêz-, âmêxtan (Proto-Iranian *āmis- ,*āmiz-; PIE *meik- "to mix"); cf. Av. mayas- "to mix;" Skt. miks- "to mix, mingle," miśr- "to mix, blend, combine;" Gk. misgein "to mix, mingle;" L. miscere (p.p. mixtus) "to mix;" O.C.S. meso, mesiti "to mix," Rus. meshat, Lith. maisau "to mix, mingle."

1) Capable of catching fire and burning; inflammable.
2) A combustible substance.

→ combustion; → -ible.

1) Any chemical reaction in which a substance (fuel) combines with oxygen to produce heat and often light. Combustion reactions usually involve a complex sequence of free-radical chain reactions. The light is produced by excited atoms, molecules, or ions.
2) → nuclear combustion.

M.E., from O.Fr. combustion, from L. combustionem (nominative combustio) "a burning," noun of action from p.p. stem of comburere "to burn," from → com-, intensive prefix + urere "to burn."

Suzeš, → burning

To approach or move toward a particular person or place.

M.E., from O.E. cuman "come, approach, arrive;" cf. Du. komen, Ger. kommen, Goth. qiman; cognate with Pers. âmadan, as below.

Âmadan "to come, to occur;" Mid.Pers. âmatan; O.Pers. gam- "to come; to go;" Av. gam- "to come; to go," jamaiti "goes;" Proto-Iranian *āgmatani; Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE root *gwem- "to go, come."

A small body of → gas and → dust which revolves around the → Sun in a usually very → elliptical or even → parabolic → orbit. It is seen to be composed of a → head, or → coma, and often with a spectacular gaseous → tail extending a great distance from the head. The rocky-icy head is called the → comet nucleus. As the comet nears the Sun, the increased temperature causes the → ice in the nucleus to → sublimate and form a gaseous halo around the nucleus, called the coma. Comets often possess two tails, a → dust tail that lies in the orbit behind the comet generated by surface activity, and a brighter, ionized → gas tail, that points away from the Sun, driven by → solar wind. → Long-period comets are thought to originate in the → Oort cloud, at distances exceeding 50,000 → astronomical units (AU). They are perturbed by the planets (especially → Jupiter) to fall in toward the Sun. Their orbits typically have random inclinations and a very large → eccentricity; some → hyperbolic orbits have been observed. → Short-period comets apparently arise in the → Kuiper belt in the zone from 20 to 50 AU. Their orbits typically have small eccentricities. Both cometary reservoirs are thought to represent primordial solar system material. A comet with a dust coating on its surface that inhibits gas production might be classified as an → asteroid. Because of this ambiguity, objects such as → Chiron, a → Centaur asteroid, have been reclassified as comets. Comets are primarily composed of amorphous → water ice, but also contain → carbon dioxide (CO₂), → carbon monoxide (CO), → formaldehyde (H₂CO), → methanol (CH₃OH), → methane (CH₄) at a few percent level (with respect to water), and many other molecules at a lower level. See also → comet designation.

From O.Fr. comète, from L. cometa, from Gk. (aster) kometes, "long-haired (star)," from kome "hair of the head," so called from resemblance of the comet's tail to streaming hair.

Dombâledâr, from dombâlé "tail," from domb, dom (Mid.Pers. dumb, Av. duma- "tail") + -âlé, -âl resemblance suffix, → -al + dâr "having, possessor," (from dâštan "to have, to possess," O.Pers./Av. root dar- "to hold, keep back, maitain, keep in mind," Skt. dhr-, dharma- "law," Gk. thronos "elevated seat, throne," L. firmus "firm, stable," Lith. daryti "to make," PIE *dher- "to hold, support").

A → comet with an irregular → nucleus of roughly 3 × 5 km across orbiting the Sun between → Jupiter and → Earth with a period of 6.45 years. The comet has been observed from Earth on seven approaches to the Sun: in 1969, 1976, 1982, 1989, 1996, 2002, and 2009. It was also imaged by the → Hubble Space Telescope in 2003, which allowed estimates of its size and shape. It arrived at → perihelion on 13 August 2015. In 2014 the → European Space Agency probe → Rosetta, launched in 2004, was placed on an orbit around 67P/Churyumov-Gerasimenko. Over an entire year, as it approached the Sun, Rosetta mapped the comet's surface and studied changes in its activity.

→ comet; Named after its discoverers, Klim Churyumov and Svetlana Gerasimenko, Ukrainian astronomers, who first noticed the comet in 1969.

A → nomenclature system for naming → comets. In early 1995, a new comet designation system was established by the → International Astronomical Union. The main rules are as follows:
a) If the comet is a newly discovered one, it first gets a provisional name, which closely matches the → asteroid designation system. For example, the first comet discovered in the first half of 1998 January is designated 1998 A1, the second 1998 A2, etc.
b) The name of the person(s) who discovered the comet may be added to this designation (limited, however, to three names). For example, comet → Hale-Bopp (C/1995 O1) has its full name as Hale-Bopp C/1995 O1, whereas its designation is C/1998 O1. If several people are involved with a discovery at an observatory, the comet may be named after the observatory instead of the individuals.
c) → Long-period comets and one-apparition → periodic comets receive only a provisional designation.
d) A → short-period comet would get the P/designation until it is recovered in a second → apparition. At this point, the P/Year designation would be replaced with a number followed immediately by an upper case P, and a slash followed by the name of the discoverer(s). The number here is one more than the number of known periodic comets that have reappeared. For example, the comet Hug-Bell (P/1999 X1) was given the full name 178P/Hug-Bell after it reappeared in 2007. Previously, 177 periodic comets had got assigned numbers.
e) Long-period comets are indicated by the prefix C.
f) If the comet is destroyed, or if it fails to appear after several apparitions, it would be prefixed D/ (→ defunct comet) followed by the year of its discovery. For example, → Comet Shoemaker-Levy 9 has been assigned D/1993 F2 since it was discovered in the second half of March in 1993 and was destroyed when it crashed into Jupiter in 1994.
g) Comets that lack sufficient position measurements for an orbital determination are given the designation of X/ followed by the year of their discovery and the appropriate letter and number code.
h) When a → comet nucleus nucleus splits, each fragment is given the comet designation followed by A, B, C, etc (for fragments).

→ comet; → designation.