An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < alp tra > >>

Number of Results: 23 Search : element
alpha element
  بن‌پار ِ آلفا   
bonpâr-e âlfâ

Fr.: élément α   

A → chemical element synthesized in → massive stars by → alpha particle capture leading to iron before the advent of a → type II supernova. Stable alpha elements are: C, O, Ne, Mg, Si, S, Ar, Ca.

alpha; → element.

alpha element knee
  زانوی ِ بن‌پار ِ آلفا   
zânu-ye bonpâr-e âlfâ


The point in the plot showing → alpha element abundances ([α/Fe]) of a galaxy as a function of the → metallicity ([Fe/H]) where the α-element abundance drops. The metallicity of the turn-over in α-element abundances is linked to the → star formation rate during the early stage of star formation in a galaxy and therefore also depends on the total mass of the system. Higher star formation efficiency leads to higher overall metallicity before the onset of → Type Ia supernova → enrichment, and thus to a knee that is located at higher [Fe/H] values.

alpha; → element; → knee.

chemical element
  بن‌پار ِ شیمیایی، عنصر ِ ~   
bonpâr-e šimiyâyi (#), onsor-e ~ (#)

Fr.: élément chimique   

A substance which consists entirely of atoms of the same → atomic number and cannot be decomposed or changed into another substance using chemical means. Currently 118 chemical elements are known, the most abundant being → hydrogen. → periodic table.

chemical; → element.

  بن‌پار، عنصر   
bonpâr (#), onsor (#)

Fr.: élément   

1) General: A component or constituent of a whole or one of the parts into which a whole may be resolved by analysis.
2) Astro.: Any of the data required to define the precise nature of an orbit and to determine the position of a planet in the orbit at any given time. → orbital element.
3) Chemistry:: One of the 117 presently known substances that cannot be decomposed by chemical reaction into a simpler substance.
4) Math.:a) Of a cylinder or cone, the generating line of the surface, taken in any position. b) Of a set, any member of the set.

From O.Fr. élément, from L. elementum "rudiment, one of the four elements, first principle," origin unknown.

Bonpâr, from bon "basis; root; foundation; bottom;" Mid.Pers. bun "root; foundation; beginning," Av. būna- "base, depth," cf. Skt. bundha-, budhná- "base, bottom," Pali bunda- "root of tree" + pâr contraction of pâré "piece, part, portion, fragment;" Mid.Pers. pârag "piece, part, portion; gift, offering, bribe;" Av. pāra- "debt," from par- "to remunerate, equalize; to condemn;" PIE *per- "to sell, hand over, distribute; to assign;" cf. L. pars "part, piece, side, share," portio "share, portion;" Gk. peprotai "it has been granted;" Skt. purti- "reward;" Hitt. pars-, parsiya- "to break, crumble." Onsor from Ar.

elemental abundance
  فراوانی ِ بن‌پار، ~ عنصر   
farâvâni-ye bonpâr, ~ onsor

Fr.: abondance élémentaire, ~ d'un élément   

Emission nebulae: The relative amount of a given → chemical element in an ionized nebula with respect to another element, usually → hydrogen. Elemental abundance ratios of → emission nebulae are obtained either by adding the observed → ionic abundances of the element or by using → ionization correction factors. Same as → total abundance.

Elemental, from M.L. elementalis, → element + -al; abundance, from O.Fr. abundance, from L. abundantia "fullness," from abundare "to overflow," from L. ab- "away" + undare "to surge," from unda "water, wave;" → abundance.

elementary particle
  ذره‌ی ِ بنیادین   
zarre-ye bonyâdin (#)

Fr.: particule élémentaire   

A particle which cannot be divided into other constituents. More specifically, a particle whose field appears in the fundamental field equations of the unified field theory of elementary particles, in particular in the Lagrangian. For example, the → electron, the → photon, and the → quark are elementary particles, whereas the proton and neutron are not. The elementary nature of a particle can be revised depending on new observations or theories. Also called → fundamental particle.

Elementary, M.E. elementare, from M.F. élémentaire, from L. elementarius, from → element + adj. suffix -arius; → particle.

Bonyâdin, from bonyâd "basis, foundation," variant of bonlâd, from bon "basis; root; foundation; bottom" → element + lâd "root; foundation; reason, cause; wall" + adj. suffix -in.

elementary time
  زمان ِ بنیادین   
zamân-e bonyâdin

Fr.: temps élémentaire   

The time required for → light to cross the classical radius of the electron (→ electron radius): te = re/c ≅ 10-23 s.

elementary particle; → time.

elements of the orbit
  بن‌پارهای ِ مدار، عنصرهای ~   
bonpârhâ-ye madâr, onsorhâ-ye ~ (#)

Fr.: éléments orbitaux   

orbital element.

element; → orbit.

heavy element
  بن‌پار ِ سنگین   
bonpâr-e sangin (#)

Fr.: élément lourd   

In astrophysics, any → chemical element heavier than → helium. Such elements are also inappropriately referred to as "→ metals."

heavy; → element.

identity element
  بن‌پار ِ ایدانی   
bonpâr-e idâni

Fr.: élément neutre   

In a mathematical system, an element which leaves unchanged any other element on which it operates. Thus 0 is the identity element for addition: a + 0 = a. And 1 is the identity element for multiplication: a . 1 = a.

identity; → element.

iron peak element
  بن‌پار ِ ستیغ ِ آهن   
bonpâr-e setiq-e âhan

Fr.: élémént du pic du fer   

A member of a group of elements with → atomic masses A about 40 to 60 that are synthesized by the → silicon burning process and appear in the → iron peak. They are mainly: → titanium (Ti), → chromium (Cr), → manganese (Mn), → iron (Fe), → cobalt (Co), and → nickel (Ni).

iron; → peak; → element.

light element
  بن‌پار ِ سبک   
bonpâr-e sabok (#)

Fr.: élément léger   

In astrophysics, a chemical element that has an atomic number of one, two, or three, such as hydrogen, helium, and lithium; sometimes also beryllium and boron.

light; → element.

mean element
  بن‌پار ِ میانگین   
bonpâr-e miyângin

Fr.: élément moyen   

An element of an adopted reference orbit that approximates the actual, perturbed orbit. Mean elements may serve as the basis for calculating perturbations.

mean; → element.

neutron-capture element
  بن‌پار ِ گیر‌افت ِ نوترون   
bonpâr-e giroft-e notron

Fr.: élément de capture de neutron   

A → nucleosynthesis process responsible for the generation of the → chemical elements heavier than the → iron peak elements. There are two possibilities for → neutron capture: the slow neutron-capture process (the → s-process) and the rapid neutron-capture process (the → r-process). The s-process is further divided into two categories: the weak s-component and the main s-component. Massive stars are sites of the weak component of s-process nucleosynthesis, which is mainly responsible for the production of lighter neutron-capture elements (e.g. Sr, Y, and Zr). The s-process contribution to heavier neutron-capture elements (heavier than Ba) is due only to the main s-component. The low- to intermediate-mass stars (about 1.3-8 Msun) in the → asymptotic giant branch (AGB) are usually considered to be sites in which the main s-process occur. There is abundant evidence suggesting that → Type II supernova (SNe II) are sites for the synthesis of the r-process nuclei, although this has not yet been fully confirmed. The observations and analysis on → very metal-poor stars imply that the stars with [Fe/H] ≤ -2.5 might form from gas clouds polluted by a few supernovae (SNe). Therefore, the abundances of → heavy elements in → metal-poor stars have been used to learn about the nature of the nucleosynthetic processes in the early Galaxy (See, e.g., H. Li et al., 2013, arXiv:1301.6097).

neutron;→ capture; → element.

orbital element
  بُن‌پارِ مداری   
bonpâr-e madâri

Fr.: élément orbital   

Any of the six parameters needed to specify the → orbit of an object around a → primary body (such as a planet around the Sun or a satellite around the Earth) and give its position at any instant. Two of them define the size and the form of the orbit: → semi-major axis (a) and → eccentricity (e). Three angular values determine the orbit position in space: the → inclination (i) of the object's → orbital plane to the reference plane (such as the → ecliptic), the → longitude of ascending node (Ω), and the → argument of periapsis (ω). And finally the sixth element is the → time of periapsis passage which allows calculating the body's position along the orbit at any instant.

orbital; → element.

osculating elements
  بن‌پارهایِ آبوسشی   
bonpârhâ-ye âbuseš

Fr.: éléments orbitaux osculateurs   

The orbital elements of an osculating orbit.

osculating; → element.

parent element
  بن‌پار ِ پرمار   
bonpâr-e permâr

Fr.: élément parent   

A radioactive element that spontaneously decays into a new substance. The product of this decay is known as a "daughter" element.

parent; → element.

platinum group element (PGE)
  بن‌پار ِ گروه ِ پلاتین   
bonpâr-e goruh-e pelâtin

Fr.: élément du groupe du platine   

One of the six metals → platinum (Pt), → iridium (Ir), → osmium (Os), → palladium (Pd), → rhenium (Rh), and → ruthenium (Ru) that are grouped together in the → periodic table. They are relatively hard and resistant to corrosion and are used in jewellery and in some industrial applications. All are resistant to chemical attack.

platinum; → group; → element.

partow bonpâr

Fr.: radioélément   

An element, such as uranium, whose isotopes are all radioactive.

radio; → element.

rare earth element
  بن‌پار ِ خاکی ِ کمیاب، خاک ِ کمیاب   
bonpâr-e xâki-ye kamyâb, xâk-e kamyâb

Fr.: terre rare   

Any of the group of metallic → chemical elements with → atomic numbers between 57 and 71 inclusive. The name is an inappropriate terminology, since they are neither rare nor earth; preferred name → lanthanide.

rare; → earth; → element.

<< < alp tra > >>