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
solar metallicity
  فلزیگی ِ خورشیدی   
felezigi-ye xoršidi

Fr.: métallicité solaire   

The proportion of the solar matter made up of → chemical elements heavier than → helium. It is denoted by Z, which represents the sum of all elements heavier than → helium, in mass fraction. The most recent determination of the solar Z gives a value of 0.0134 (Asplund et al. 2009, ARAA 47, 481), corresponding to the present-day photospheric composition.

solar; → metallicity.

solar minimum
  کمینه‌ی ِ خورشیدی   
kamine-ye xoršidi

Fr.: minimum solaire   

The month(s) during the 11 year → solar cycle when the number of → sunspots is lowest.

solar; → minimum.

solar nebula
  میغ ِ خورشیدی   
miq-e xoršidi

Fr.: nébuleuse solaire   

The cloud of interstellar gas and dust from which the Sun and the rest of the solar system initially formed.

solar; → nebula.

solar neighborhood
  همسایگی ِ خورشید   
hamsâyegi-ye xoršid (#)

Fr.: voisinage solaire   

That part of the Milky Way galaxy lying near the Sun. In fact there is no definition of the exact radius of this region. It is referred to the immediate solar neighborhood (within about 5 pc), the solar neighborhood (within about 25 pc), and the extended solar neighborhood (within a few hundred pc).

solar; → neighborhood.

solar neutrino
  نوترینوی ِ خورشیدی   
notinohâ-ye xoršidi

Fr.: flux des neutrinos solaires   

A neutrino generated in the → Sun. The main source of solar neutrinos is the → proton-proton chain of reactions: 4 × p→ He + 2e+ + 2νe, in which an energy of +28 MeV is shared between the reaction products. These are called → low-energy neutrinos. There are less important reactions in the Sun yielding a smaller flux of higher energy neutrinos. The solar neutrino flux can be estimated from the → solar luminosity (L), as follows Since there are two neutrinos for each 28 MeV of energy, the neutrino flux at the Earth distance (d) is given by: ν flux = 2Lsun/(28 MeV) × (1/4πd2) = 6 × 1010 cm-2 s-1. See also the → solar neutrino problem.

solar; → neutrino; → flux.

solar neutrino problem
  پراسه‌ی ِ نوترینوهای ِ خورشید   
parâse-ye notrinohâ-ye xoršid

Fr.: problème des neutrinos solaires   

A major discrepancy between the flux of neutrinos detected at Earth from the solar core and that predicted by current models of solar nuclear fusion and our understanding of neutrinos themselves. The problem, lasting from the mid-1960s to about 2002, was a considerably lesser detected number of neutrons compared with theoretical predictions. The discrepancy has since been resolved by new understanding of neutrino physics, requiring a modification of the → standard model of particle physics, in particular → neutrino oscillation.

solar; → neutrino; → problem.

solar neutrino unit (SNU)
  یکای ِ نوترینوهای ِ خورشیدی   
yekâ-ye notrinohâ-ye xoršidi

Fr.: unité de neutrinos solaires   

A measure of the flux of neutrinos from the Sun reaching the Earth. 1 SNU is equal to 10-36 solar neutrinos captured per target atom per second.

solar; → neutrino; → unit.

solar parallax
  دیدگشت ِ خورشیدی   
didgašt-e xoršidi

Fr.: parallaxe solaire   

The angle subtended (8''.79) by the → equatorial radius of the Earth at a distance of 1 → astronomical unit.

solar; → parallax.

solar photospheric abundance
  فراوانی ِ شیدسپهری ِ خورشیدی   
farâvâni-ye šidsepehri-ye xoršidi

Fr.: abondance photosphérique solaire   

The abundance of a → chemical element as determined from the observation of solar → spectral lines. The solar chemical composition is an important ingredient in our understanding of the formation, structure and evolution of both the Sun and our solar system. Furthermore, it is an essential reference standard against which the elemental contents of other astronomical objects are compared (Asplund et al. 2009, arXiv:0909.0948). The photospheric abundances relative to hydrogen are not representative of the → protosun, or global → solar system abundances. This is because heavy-element fractionation in the Sun has altered photospheric abundances (Lodders 2003, ApJ 591, 1220).

solar; → photospheric; → abundance.

solar physics
  فیزیک ِ خورشیدی   
fizik-e xoršidi

Fr.: physique solaire   

The branch of astrophysics concerned with the study of the physical properties of the Sun based on the most detailed observations which can be obtained for a star.

solar; → physics.

solar power
  توان ِ خورشیدی   
tavân-e xoršidi

Fr.: puissance solaire   

Any power obtained by converting solar radiation into useful power.

solar; → power.

solar probe
  گمانه‌ی ِ خورشیدی   
gomâne-ye xoršidi

Fr.: sonde solaire   

A space probe designed to gather data about the Sun.

solar; → probe.

solar prominence
  زبانه‌ی ِ خورشیدی   
zabâne-ye xoršidi

Fr.: protubérances solaires   

A large, arch-shaped filament of hot gas extending outward from the Sun's surface. More at → prominence.

solar; → prominence.

solar radiation
  تابش ِ خورشیدی   
tâbeš-e xoršidi

Fr.: rayonnement solaire   

All the constituents making up the Sun's emission: photons, electrons, protons, neutrinos, and atomic nuclei.

solar; → radiation.

solar radiation pressure
  فشار ِ تابش ِ خورشید   
fešâr-e tâbeš xoršid (#)

Fr.: pression du rayonnement solaire   

The → radiation pressure of solar photons, which pushes a comet's dust outward to form a → dust tail.

solar; → radiation; → pressure.

solar radius
  شعاع ِ خورشید   
šo'â'-e xoršid

Fr.: rayon solaire   

A unit of length, representing the radius of the → Sun, used to express the size of stars in astrophysics. It is equivalent to: 695,700 km, 0.00465047 → astronomical units, 7.35355 × 10-8 → light-years, and 2.32061 → light-seconds.

solar; → radius.

solar rotation
  چرخش ِ خورشید   
carxeš-e xoršid (#)

Fr.: rotation du Soleil   

The motion of the Sun around an axis which is roughly perpendicular to the plane of the → ecliptic; the Sun's rotational axis is tilted by 7.25° from perpendicular to the ecliptic. It rotates in the → counterclockwise direction (when viewed from the north), the same direction that the planets rotate (and orbit around the Sun). The Sun's rotation is differential, i.e. the period varies with latitude on the Sun (→ differential rotation). Equatorial regions rotate in about 25.6 days. The regions at 60 degrees latitude rotate more slowly, in about 30.9 days.

solar; → rotation.

solar satellite
  بنده‌وار ِ خورشیدی   
bandevâr-e xoršidi

Fr.: satellite solaire   

A space vehicle designed to orbit about the Sun.

solar; → satellite.

solar spectrum
  بیناب ِ خورشید، ~ خورشیدی   
binâb-e xoršid (#), ~ xoršidi (#)

Fr.: spectre solaire   

The spectrum of the Sun's electromagnetic radiation, consisting of a continuum spectrum marked with dark absorption lines.

solar; → spectrum.

solar system
  راژمان ِ خورشیدی   
râšmân-e xoršidi

Fr.: Système solaire   

The collective name for the Sun and all objects gravitationally bound to it. These objects are the eight planets, their 166 known moons, five dwarf planets, and billions of small bodies. The small bodies include asteroids, icy Kuiper belt objects, comets, meteoroids, and interplanetary dust. The solar system is roughly a sphere with a radius greater than 100,000 AU. Planets, satellites, and all interplanetary material together comprise only about 1/750 of the total mass. Geochemical dating methods show that the solar system chemically isolated itself from the rest of the Galaxy (4.7 ± 0.1) × 109 years ago.

solar; → system.

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