An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1223

Fr.: grumelage   

The massing together of material to form clumps. → wind clumping.

clump; → -ing.

clumping factor
  کروند ِ گوده‌داری   
karvand-e gudedâri

Fr.: facteur de grumelage   

The ratio fcl = <ρ2> / <ρ >2, where ρ represents the → stellar wind density and the brackets mean values. Unclumped wind has fcl = 1 and → clumping becomes significant for fcl≅ 4.

clumping; → factor.


Fr.: grumeleux   

Of a → molecular cloud, being composed of → clumps.

Clumpy, from → clump + -y suffix meaning "full of or characterized by," from O.E. -ig, from P.Gmc. *-iga, akin to Gk. -ikos, L. -icus, → -ics.

Gudedâr, from gudé, → clump, + 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."

  ۱) خوشه؛ ۲) خوشه‌بستن   
1) xušé (#); 2) xušé bastan (#)

Fr.: 1) amas; 2) s'agglomérer, se grouper   

1) A group of the same astronomical objects gathered or occurring closely together, such as → cluster of galaxies, → globular cluster, → open cluster, and so on.
2) To gather or grow into clusters. → Arches cluster, → Beehive Cluster, → bound cluster, → Brocchi's Cluster, → Bullet cluster, → Central cluster, → cluster core, → cluster mass function, → cluster of galaxies, → clustering, → clustering law, → Coma cluste, → Galactic center cluster, → galactic cluster, → galaxy cluster, → globular cluster, → Hercules cluster, → hierarchical clustering, → intercluster medium, → Local Supercluster, → moving cluster, → open cluster, → Perseus Cluster, → pre-cluster core, → protocluster, → rich cluster, → S cluster, → Sgr A* cluster, → star cluster, → super star cluster, → supercluster, → superclustering, → tight star cluster, → Trapezium cluster, → unbound cluster, → Ursa Major cluster.

O.E. clyster "cluster," probably akin to O.E. clott "clot".

Xušé "cluster, a bunch of grapes, an ear of corn," (Laki huša), from Mid.Pers. hošag or xušak; cf. Skt. guccha- "bundle, bunch of flowers, cluster of blossom, clump;" xušé bastan, with bastan "to bind, shut; to clot; to form seed buds", from Mid.Pers. bastan/vastan "to bind, shut," Av./O.Pers. band- "to bind, fetter," banda- "band, tie," Skt. bandh- "to bind, tie, fasten," PIE *bhendh- "to bind," cf. Ger. binden, E. bind.

cluster core
  مغزه‌ی ِ خوشه   
maqze-ye xušé

Fr.: cœur d'amas   

The central part of a cluster (globular, galaxies, etc.) where the spatial density of the objects making up the cluster is much higher than the average value.

cluster; → core.

cluster mass function (CMF)
  کریای ِ جرم ِ خوشه   
karyâ-ye jerm-e xušé

Fr.: fonction de masse d'amas   

An empirical power-law relation representing the number of clusters as a function of their mass. It is defined as: N(M)dM ∝ MdM, where the exponent α has an estimated value of about 2 and dM is the mass interval. It is believed that this is a universal law applying to a variety of objects including globular clusters, massive young clusters, and H II regions.

cluster; → mass; → function.

cluster of galaxies
  خوشه‌ی ِ کهکشانی   
xuše-ye kahkašâni (#)

Fr.: amas de galaxies   

Same as → galaxy cluster.

cluster; → galaxy.

xušé bandi

Fr.: agglomération, groupement   

Grouping of a number of similar astronomical objects.

Noun from verb → cluster.

clustering law
  قانون ِ خوشه‌بندی   
qânun-e xušé bandi

Fr.: loi de groupement   

An empirical power-law representing the number of stellar clusters as a function of the number of stars per cluster within an interval. It is expressed as: N(N*) dN*∝ N* dN*, where N(N*) is the number of clusters containing N* stars and dN* is the interval in star number. It is believed that this relationship applies to a variety of systems, including stellar clusters, globular clusters, H II regions (Oey et al. 2004, AJ 127, 1632).

clustering; → law.



A disorderly heap or assemblage; a state or condition of confusion.

Variant of clotter (now obsolete), from to clot + -er.

Âluzé, from Kurd. âluz, Tabari âluz, âliz "messy, disorderly, untidy," Dehxodâ âlofté "astonished; mad; broken," âloftan "to rage, grow mad."


Fr.: CMB   

See → cosmic microwave background radiation (CMBR).

CMB, short for → Cosmic  → Microwave  → Background.

CMB angular power spectrum
  بیناب ِ توانی ِ زاویه‌ای ِ CMB   
binâb-e tavâni-ye zâviye-yi-e CMB

Fr.: spectre de puissance angulaire du CMB   

A plot displaying the amplitude of → cosmic microwave background anisotropy as a function of angular size or → multipole index. Same as → angular fluctuation spectrum. The plot, based the on WMAP and other data, shows a plateau at large angular or length scales (→ Sachs-Wolfe plateau), then a series of peaks at progressively smaller scales. These features arise from the gravity-driven acoustic oscillations of the coupled photon-baryon fluid in the early Universe (→ baryon acoustic oscillation). In particular, a strong peak is seen on an angular scale (at l ~220), corresponding to the physical length of the → sound horizon at the → recombination era. It depends on the curvature of space. If space is positively curved, then this sound horizon scale will appear larger on the sky than in a flat Universe (the first peak will move to the left). The second peak (l ~ 550), which is the first harmonic of the main peak, relates to the baryon/photon ratio. The third peak can be used to help constrain the total matter density.

angular; → fluctuation; → spectrum.

CMB lensing
  لنزش ِ CMB   
lenzeš-e CMB

Fr.: effet de lentille du rayonnement du fond cosmique, ~ ~ du CMB   

The gravitational effect of the intervening large-scale potentials on the → cosmic microwave background radiation (CMBR). This effect smoothes out the temperature peaks and alters the statistics of the CMB.

CMB; → lensing.

CN molecule
  مولکول ِ CN   
molekul-e CN

Fr.: molécule CN   

The simplest molecule formed by the → cyano radical. The CN molecule is of considerable astrophysical importance, since many of its transition lines/bands are observed in various astronomical objects: interstellar medium, comets, various stars such as late-type F and G-dwarfs, and late-type giants. CN was the second interstellar molecule, after → CH (methylidine), to be identified; toward the bright star → Zeta Ophiuchi at ultraviolet wavelengths (A. McKellar, 1940 ASP Conf. Ser. 52, 187). CN was also one of the earliest molecules to be detected in other galaxies (Henkel et al. 1988, A&A 201L, 23).

cyano-; → molecule.


Fr.: CNO   

Referring to → carbon, → nitrogen, and → oxygen, as in → CNO cycle and → CNO star.


CNO cycle
  چرخه‌یِ CNO   
carxe-ye CNO (#)

Fr.: cycle CNO   

A series of → nuclear reactions taking place in stars in which → carbon, → nitrogen, and → oxygen are used to transform → hydrogen into → helium. In → massive stars the carbon cycle is the dominant process of energy generation, whereas in → low-mass stars such as the Sun, the → proton-proton chain of reactions converts hydrogen into helium. The carbon cycle starts and ends with carbon-12, which acts as a catalyst in the sequential production of helium from hydrogen; neutrinos and gamma rays are also produced.

CNO; → cycle.

CNO star
  ستاره‌ی ِ CNO   
setâre-ye CNO

Fr.: étoile CNO   

A late → O-type star or an early → B-type star in whose spectrum the lines of some of the elements → carbon (C), → nitrogen (N), and → oxygen (O) are present.

CNO; → star.

CO formation
  دیسش ِ CO   
diseš-e CO

Fr.: formation de CO   

The chemical reaction that gives rise to → carbon monoxide in the → interstellar medium. According to models, several processes may lead to CO formation. For example, HCO+ + e → CO + H. The molecule HCO+ is itself produced through several paths, for example: H3+ + C → CH2+ + H, CH2+ + H2 → CH3+ + H, CH3+ + O → HCO+ + H. Alternatively: C+ + H2O → HCO+ + H. Another possibility: C+ + OH → CO+ + H, CO+ + H2→ HCO+ + H.

carbon monoxide; → formation.

ham- (#)

Fr.: co-   


co-added image
  تصویر ِ هم‌افزوده   
tasvir-e hamafzudé

Fr.: image intégrée   

An image made up of several individual images of relatively short exposure times which are added together in order to produce a final image of higher quality.

Co-added, from → co- "together" + added p.p. of → add; → image.

Tasvir, → image; hamafzudé from ham- "together", → com-, + afzudé p.p. of afzudan, → add.

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