An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1290
  گیر‌افت، گیر‌اندازی   
gir-oft, gir-andâzi (#)

Fr.: capture   

The process in which an atomic, nuclear, or astronomical system acquires an additional particle or body.

From M.Fr. capture "a taking," from L. captura "a taking," from captus p.p. of capere "to take, hold, seize;" PIE base *kap- "to grasp" (cf. Skt. kapati "measure equal to the capacity of the hollows of the two hands joined;" Gk. kaptein "to swallow;" O.Ir. cacht "servant-girl," literally "captive;" Goth. haban "have, hold;" O.E. habban, E. have "to have, hold;" probably Mod.Pers. qâp-, qâpidan, kapidan "to seize, rob").

Gir-oft, composite verb from gir + oft. Gir "take, seize, hold," from gereftan, from O.Pers./Av. grab- "to take, seize," cf. Skt. grah-, grabh- "to seize, take," graha- "seizing, holding, perceiving," M.L.G. grabben "to grab," from P.Gmc. *grab, E. grab "to take or grasp suddenly;" PIE *ghrebh- "to seize." Oft, from oftâtan "to fall; to befal, happen," Mid.Pers. opastan, Av. pat- " to fly, fall, rush," Skt. patati "he flies, falls," L. petere "to fall, rush out," Gk. piptein "to fall," PIE base *pet- "to fly, to rush." Gir-andâzi, from gir + andâzi, verbal noun from gir-andâxtan "to throw, cast; to do, make."


Fr.: carbo-   

A combining form used in the names of → chemical compounds in which → carbon is present. Also, especially before a vowel, carb-.

From → carbon.


Fr.: glucide, hydrate de carbone   

A molecular compound made from just three → chemical elements: → carbon, → hydrogen, and → oxygen. Carbohydrates have the general molecular formula CxH2yOy, and thus were once thought to represent "hydrated carbon." However, the arrangement of atoms in carbohydrates has little to do with → water molecules. Carbohydrates are a source of energy for the body. They include sugars, starches, cellulose and many other compounds found in living organisms. In their basic form, carbohydrates are simple sugars or monosaccharides.

carbo-; → hydrate.

karbon (#)

Fr.: carbone   

Nonmetallic chemical element; symbol C. → Atomic number 6; → atomic weight 12.011; → melting point about 3,550°C; → boiling point 4,827°C. The most abundant isotope of carbon is 12C. Carbon is one of the most important elements for life. The burning of carbon in the form of coal and oils has been essential in the development of industrial societies. It is the element that hardens → steel and the sole element in → diamonds. The carbon in nature is produced inside massive stars. → triple-alpha process; → Hoyle state.

Carbon, from Fr. carbone, coined by Antoine Lavoisier (1743-1794) to distinguish it from charbon (Fr.) "charcoal," from L. carbo (genitive carbonis) "a coal, charcoal."

carbon burning
  سوزش ِ کربون   
suzeš-e karbon

Fr.: combustion du carbon   

The stage in the evolution of a star after → helium burning when the core of the star consists mainly of carbon and oxygen. In stars of mass greater than about 8 solar masses, whose cores reach a temperature above 5 × 108 K and density above 3 × 109 kg m-3, carbon burning can begin via reactions such as the following:
12C + 12C → 20Ne + 4He
12C + 12C → 23Na + p
12C + 12C → 23Mg + n.
The time-scale for this phase of → nucleosynthesis is of order of five hundred years.

carbon; → burning.

carbon crisis
  پرژنه‌ی ِ کربون   
paržane-ye karbon

Fr.: crise du carbone   

A problem raised in the past by observations suggesting that the amount of carbon necessary for standard → dust models was larger than what actually observed for the → interstellar medium (ISM) (Snow & Witt 1995). The problem was especially acute for the → 2175 A bump in the ultraviolet part of the → extinction curve. The so-called "crisis" was finally solved by, on the one hand, revising downward the → solar abundances, thought to represent the ISM abundances (Asplund et al. 2009, arXiv:0909.0948, and references therein), and, on the other hand, revising upward the ISM carbon abundances (Sofia et al., 2011, AJ 141, 22S).

carbon; → crisis.

carbon cycle
  چرخه‌ی ِ کربون   
carxe-ye karbon (#)

Fr.: cycle du carbone   

1) A complex series of processes through which all the carbon atoms on Earth is cycled through the air, ground, plants, animals, and fossil fuels. During the cycle, plants absorb → carbon dioxide (CO2) from the atmosphere and through → photosynthesis incorporate the associated carbon atoms into sugars and other molecules necessary for growth. Plants return carbon atoms back to the atmosphere in the form of CO2. However, much of the carbon absorbed remains "locked up" in the living organisms until decomposition or fire releases it back to the atmosphere.
2) For nuclear fusion in stars → CNO cycle.

carbon; → cycle.

carbon dioxide
  دی‌اکسید ِ کربون، گاز کربونیک   
dioksid-e karbon, gâz karbonik (#)

Fr.: dioxyde de carbone   

CO2, also called carbonic acid gas. A colorless gas which occurs in the atmosphere playing an essential part in animal respiration and the growth of green plants. → photosynthesis, → carbon cycle. It is formed by the → oxidation of carbon and carbon compounds. Carbon dioxide is the most important → greenhouse gas produced by human activities, primarily through the combustion of fossil fuels. Its concentration in the Earth's atmosphere has risen by more than 30% since the Industrial Revolution. CO2 forms a solid at -78.5 °C at atmospheric pressure, and is used as a refrigerant in this form as a dry ice for the preservation of frozen foods. As carbon dioxide gas is heavier than air and does not support combustion, it is used in fire extinguishers.
CO2 is present in the → interstellar medium and is one of the main → molecules in → comets.

carbon; → dioxide.

carbon monoxide (CO)
  مونوکسید ِ کربون   
monoksid-e karbon (#)

Fr.: monoxyde de carbone   

A colorless, odorless, very poisonous gas which burns in air with a bright blue flame to form → carbon dioxide. CO gives rise to a violent explosion when ignited in air in certain proportions. It occurs in coal gas and in the exhaust fumes of motor engines. Melting point -207 °C; boiling point -191.1 °C.
Carbon monoxide is the most important → molecule found in the → interstellar medium, and is produced through several chemical reactions, → CO formation. It was discovered in 1970 by R. Wilson and A. Penzias of Bell Laboratories, using the 11-m telescope of the National Radio Astronomy Observatory (NRAO) in the direction of the → Orion nebula. Because the CO line is so intense and widely distributed in space, this molecule is a most useful tool for tracing the ISM. In addition, measurement of its rare isotopes have shown that the main line 12C16O (wavelength 2.6 mm, 115 GHz) is → optically thick, that is the → column density of the molecule is so high that the material becomes opaque at the transition frequency. Moreover, the upper-energy levels of the CO molecule are easily excited by collision with → molecular hydrogen. The combination of high → optical depth and the ease of → excitation imply that CO emission brightness will accurately reflect the local gas temperature. CO is also one of the principal molecules detected in → comet nuclei.

carbon; → mono-; → oxide.

carbon star
  ستاره‌ی ِ کربونی   
setâre-ye karboni

Fr.: étoile carbonée   

A class of → red giant stars whose spectra show strong → molecular bands of → carbon compounds.

carbon; → star.


Fr.: carbon-14   

A radioactive isotope of carbon, whose nucleus contains 6 protons and 8 neutrons; also called → radiocarbon. 14C is naturally produced in the atmosphere when a neutron created by a cosmic ray hits the nucleus of an atom of nitrogen-14. The nucleus absorbs the neutron and ejects a proton, thereby transforming itself into 14C. It decays back to nitrogen, with a half-life is 5730 years, after emitting an electron (146C → 147N + e- + νe). See also → radiocarbon dating.

carbon; → four + -teen, an inflected form of the root of → ten.

carbon-enhanced metal-poor star (CEMP)
  ستاره‌ی ِ کم‌فلز ِ کربون بلندیده   
setâre-ye kamfelez-e karbon bolandidé

Fr.: étoile pauvre en métaux enrichie en carbon   

A star that presents very low → iron  → abundances [Fe/H] < -4 but an → anomalous richness in carbon. CEMP stars have been defined as a subset of → metal-poor stars that exhibit elevated [C/Fe] ≥ +1.0. It has been recognized that ~15-20% of stars with [Fe/H] < -2.0 are carbon enhanced. This fraction rises to 30% for [Fe/H] < -3.0, to 40% for [Fe/H] < -3.5, and ~75% for [Fe/H] < -4.0. This increasing trend of CEMP-star frequency with declining [Fe/H] is confirmed by the observation of many thousands of CEMP stars (Daniela Carollo + ApJ 2014, 788, 180). See also → extremely metal-poor star (EMPS)

carbon; → enhance; → metal; → metal; → poor; → star.

  کربونی، کربندار   
karboni, karbondâr

Fr.: carboné   

Containing or composed of carbon.

From → carbon + -aceous, from L. -aceus "-ous."

Karboni, adj. from karbon, → carbon; karbondâr "having carbon," with -dâr "having, possessor," from dâštan "to have, to possess;" O.Pers./Av. root dar- "to hold, keep back, maintain, keep in mind;" cf. Skt. dhr-, dharma- "law;" Gk. thronos "elevated seat, throne;" L. firmus "firm, stable;" Lith. daryti "to make;" PIE base *dher- "to hold, support."

carbonaceous chondrite
  کوندریت ِ کربونی   
kondrit-e karboni

Fr.: chondrite carbonée   

A rare type of → stony meteorite having a higher → carbon content than other classes of meteorite. They represent only ~5% of the known meteorites. Their bulk composition is mainly → silicates, → oxides and sulfides, whilst the minerals → olivine and serpentine are characteristic. The six classes of carbonaceous chondrites are: → CI chondrites, CM chondrites, CV chondrites, CO chondrites, CK chondrites, CR chondrites, CH chondrites, and CB chondrites.

carbonaceous; → chondrite.

carbonyl group
  گروه ِ کربونیل   
goruh-e karbonil (#)

Fr.: groupe carbonyl   

The radical -C=O, which occurs in several compounds, such as → aldehydes and ketones.

From → carbon + -yl a suffix used in the names of some radicals; → group.

carboxyl radical (COOH)
  رادیکال ِ کربوکسیل   
râdikâl-e karboksil (#)

Fr.: radical carboxyl   

Chem.: The -COOH group, regarded as the essential and characteristic constituent of organic acids.

From carb-, variant of carbo- before a vowel, from → carbon, + ox, from → oxygen, + -yl a suffix used in the names of radicals.


Fr.: cardinal   

1) Fundamentally → important; → principal.
2) → cardinal number.

M.E., from L.L. cardinalis "principal, pivotal," lit. "serving as a hinge," from cardo, cardin- "door hinge."

Agrâ, from Av. aγra-, aγrya- "the highest, the first, foremost" cf. Skt. agra- "foremost, first, prominent," PIE *agro- "top, first, beginning."

cardinal direction
  سوی ِ اگرا   
su-ye agrâ

Fr.: point cardinal   

Any of the four principal directions or points of the compass, → north, → east, → south, and → west. See also: → cardinal point.

cardinal; → direction.

cardinal number
  عدد ِ اگرا   
adad-e agrâ

Fr.: nombre cardinal   

An ordinary number such as 0, 1, 2, or 3, as opposed to an → ordinal number such as 1st, 2nd, or 3rd. Cardinal numbers can be → zero or → positive and are used for counting the things that are assumed to be not divisible.

cardinal; → number.

cardinal point
  نقطه‌ی ِ اگرا   
noqte-ye agrâ

Fr.: point cardinal   

One of the four points where the → meridian and the → prime vertical intersect the → horizon. See also: → cardinal direction.

cardinal; → point.

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