An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1307
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 radii
  شعاع(های) ِ خورشید   
šo'â'(hây)-e xoršid

Fr.: rayons solaires   

Plural form of → solar radius.

solar; → radii.

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.

solar system abundance
  فراوانی ِ راژمان ِ خورشیدی   
farâvâni-ye râžmân-e xoršidi

Fr.: abondance dans le système solaire   

Same as → protosolar abundance.

solar system; → abundance.

solar telescope
  تلسکوپ ِ خورشیدی، دوربین ِ ~   
teleslop-e xoršidi, durbin-e ~

Fr.: télescope solaire   

A telescope designed so that heating effects produced by the Sun do not distort the images.

solar; → telescope.

solar time
  زمان ِ خورشیدی   
zamân-e xoršidi (#)

Fr.: temps solaire   

The time based on the rotation of the Earth relative to the Sun. → mean solar time.

solar; → time.

solar tower
  برج ِ خورشیدی   
borj-e xoršidi

Fr.: tour solaire   

A structure used in solar observations in order to raise the equipment above the atmospheric disturbances caused by solar heating of the ground and the radiation of the heat into the atmosphere.

solar; → tower.

solar twin
  همزاد ِ خورشید   
hamzâd-e xoršid

Fr.: jumeau du soleil   

An ideal star possessing fundamental physical parameters (mass, chemical composition, age, effective temperature, luminosity, gravity, magnetic fields, equatorial rotation, etc.) very similar, if not identical, to those of the Sun. See also → solar analog; → solar-like star.

solar; → twins paradox.

solar velocity
  تندای ِ خورشید، ~ خورشیدی   
tondâ-ye xoršid, ~ xoršidi

Fr.: vitesse solaire   

The rate of change of the Sun's position with respect to the local standard of rest toward the → solar apex.

solar; → velocity.

solar wind
  باد ِ خورشید، ~ ِ خورشیدی   
bâd-e xoršid, ~ xoršidi

Fr.: vent solaire   

A mass outflow, consisting of protons, electrons, and other subatomic particles, expelled constantly from the solar corona at about 500 km per second. The solar mass-loss rate in this phenomenon amounts to about 2 x 10-14 solar masses per year, or about 106 tons per second. → stellar wind.

solar; → wind.

solar year
  سال ِ خورشیدی   
sâl-e xoršidi (#)

Fr.: année solaire   

The period of time required for the Earth to make one complete revolution around the Sun. Solar year is a general term for: → tropical year, → vernal equinox year, and → autumnal equinox year, which have different lengths.

solar; → year.

solar-like star
  ستاره‌ی ِ خورشیدمانند   
setâre-ye xoršid-mânand

Fr.: étoile semblable au soleil   

A member of a very broad class of stars in which is found a mixture of late F, early, middle, and, sometimes, late G type dwarfs and sub-giants. See also → solar analog; → solar twin.

solar; → -like; → star.

solar-terrestrial phenomena
  پدیده‌های ِ خورشیدی-زمینی   
padidehâ-ye xoršidi-zamini

Fr.: phénomènes solaires-terrestres   

Any of the various phenomena observable on the Earth that are caused by the influence of the Sun, such as aurora borealis.

solar; → terrestrial; → phenomenon.

Solberg-Hoiland criterion
  سنجیدار ِ سولبرگ-هویلاند   
sanjidâr-e Solberg-Høiland

Fr.: critère de Solberg-Høiland   

A criterion for → convective stability in → massive stars. The Solberg-Høiland stability criterion corresponds to the inclusion of the effect of → rotation (variation of → centrifugal force) in the convective stability criterion. It is a combination of → Ledoux's criterion (or possibly → Schwarzschild's criterion) and → Rayleigh's criterion. Both the dynamical shear and Solberg-Høiland instabilities occur in the case of a very large → angular velocity decrease outwards. Therefore, in a → rotating star the Ledoux or Schwarzschild criteria for convective instability should be replaced by the Solberg-Høiland criterion. More specifically, this criterion accounts for the difference of the centrifugal force for an adiabatically displaced fluid element. It is also known as the axisymmetric baroclinic instability. It arises when the net force (gravity + buoyancy + centrifugal force) applied to a fluid parcel in an adiabatical displacement has components only in the direction of the displacement (A. Maeder, Physics, Formation and Evolution of Rotating Stars, 2009, Springer).

E. Høiland, 1939, On the Interpretation and Application of the Circulation Theorems of V. Bjerknes. Archiv for mathematik og naturvidenskab. B. XLII. Nr. 5. Oslo.
H. Solberg, 1936 (reprint), Le mouvement d'inertie de l'atmosphere stable et son rôle dans la théorie des cyclones.
H. Solberg, 1941, On the Stability of the Circular Vortex. Avhandl. utg. av Det Norske Videnskaps-Akademi i Oslo. I. Mat-Naturv. Klasse. No. 11.
Wasiutynski, J. 1946, Astrophysica Norvegica, 4, 1.

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