An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 707
rotation curve
  خم ِ چرخش   
xam-e carxeš

Fr.: courbe de rotation   

A plot of the variation in → orbital velocity of stars and → interstellar matter with distance from the center of a → galaxy. A "flat" rotation curve indicates that the mass of the galaxy increases linearly with distance from its center. See also: farsi→ Keplerian rotation curve

Rotation; → curve.

rotation energy
  کاروژ ِ چرخش   
kâruž-e carxeš

Fr.: énergie de rotation   

The → kinetic energy of rotational motion of an object. It is expressed by ER = (1/2)Iω2, where I is the → moment of inertia and ω → angular velocity (2π/P).

rotation; → energy.

rotation frequency
  بسامد ِ چرخش   
basâmad-e carxeš

Fr.: fréquence de rotation   

The number of rotations per unit time of a rotating object.

rotation; → frequency.

rotation period
  دوره‌ی ِ چرخش   
dowre-ye carxeš (#)

Fr.: période de rotation   

The interval of time during which an object turns once about its axis.

rotation; → period.

rotation-induced turbulence
  آشوبناکی ِ زاییده‌ی ِ چرخش، ~ درهازیده از ~   
âšubnâki-ye zâyide-ye carxeš, darhâzidé az ~

Fr.: turbulence induite par turbulence   

A type of → turbulence with motions more vigorous in the horizontal than in the vertical direction occurring in internal radiation zone of → rotating stars. Same as → shear turbulence.

rotation; → induced; → turbulence.

rotation-powered pulsar (RPP)
  تپار ِ چرخش-توان، پولسار ِ ~ ~   
tapâr-e carxeš-tavân, pulsâr-e ~ ~

Fr.:   

A → neutron star that is spinning down as a result of → torques from → magnetic dipole radiation and particle emission. RPPs derive their energy primarily from the → rotation of the neutron star. The energy from their → spin-down appears as broad-band pulsations from → radio to → gamma-ray wavelengths and as a → wind of energetic particles flowing into their surrounding → pulsar wind nebulae. Since the discovery of RPPs through their radio → pulsations in 1967, more than 2000 → radio pulsars are now known with periods ranging from a few milliseconds to several seconds (A. K. Harding, 2013, Front. Phys. 8, 679).

rotation; → power; → pulsar.

rotation-vibration spectrum
  بیناب ِ چرخش-شیوش   
binâb-e carxeš-šiveš

Fr.: spectre rotation-vibration   

The spectrum of a molecule resulting from the simultaneous rotation and vibration of its constituent atoms.

rotation; → vibration; → spectrum.

rotational
  چرخشی   
carxeši (#)

Fr.: rotationnel   

Of or pertaining to → rotation.

Rotational, adj., from → rotation + → -al.

rotational angular momentum
  جنباک ِ زاویه‌ای ِ چرخشی   
jonbâk-e zâviyeyi-ye carxeši

Fr.: moment angulaire rotationnel, moment cinétique ~   

The → angular momentum of a body rotating about an axis. The rotational angular momentum of a solid homogeneous sphere of mass M and radius R rotating about an axis passing through its center with a period of T is given by: L = 4πMR2/5T.

rotational; → angular; → momentum.

rotational axis
  آسه‌ی ِ چرخش   
âse-ye carxeš

Fr.: axe de rotation   

An imaginary line about which a solid object rotates. Same as → rotation axis and → axis of rotation.

rotational; → axis.

rotational broadening
  پهنش ِ چرخشی   
pahneš-e carxeši

Fr.: élargissement rotationnel   

The spectral line broadening caused by stellar rotation. Light from two rims of the star will be Doppler shifted in opposite directions, resulting in a line broadening effect. The line broadening depends on the inclination of the star's pole to the line of sight. The derived value is a function of ve. sini, where ve is the rotational velocity at the equator and i is the inclination, which is not always known. The fractional width (Δλ/λ) is of the order of 10-3 for B stars.

rotational; → broadening.

rotational Eddington limit
  حد ِ ادینگتون ِ چرخشی   
hadd-e Eddington-e carxeši

Fr.: limite d'Eddington avec rotation   

The → Eddington limit of luminosity for a → rotating star in which both the effects of → radiative acceleration and rotation are important. Such objects mainly include → OB stars, → LBV, → supergiants, and → Wolf-Rayet stars. It turns out that the maximum permitted luminosity of a star is reduced by rotation, with respect to the usual Eddington limit (Maeder & Meynet, 2000, A&A, 361, 159).

rotational; → Eddington limit.

rotational energy
  کاروژ ِ چرخشی   
kâruš-e carxeši

Fr.: énergie rotationnelle   

The → kinetic energy due to the → rotation of and object. Rotational energy is part of the total kinetic energy of the body. It is given by: (1/2)Iω2, where I is the → moment of inertia and ω is the → angular velocity. Same as → angular kinetic energy.

rotational; → energy.

rotational mixing
  آمیزش ِ چرخشی   
âmizeš-e carxeši

Fr.: mélange rotationnel   

A consequence of → stellar rotation that deforms the star, triggers instabilities (→ shear turbulence and → meridional currents) leading to → transport of chemical species in the star. The efficiency of rotational mixing (measured for instance by the degree of surface → enrichments at a given → evolutionary stage) increases when the initial mass and rotation increase. This efficiency increases also when the initial → metallicity decreases. This is due to the fact that when the metallicity is lower, the stars are more compact. This makes the → gradients of the → angular velocity steeper in the stellar interiors. Steeper gradients produce stronger shear turbulence and thus more mixing. Rotational mixing can bring to the surface heavy elements newly synthesized in the stellar core. Rotation thus produces an increase of the → opacity of the outer layers and activates strong → mass loss through → radiatively driven winds. This effect may be responsible for the loss of large fractions of the initial mass of the star (Meynet et al. 2007, arXiv:0709.2275).

rotational; → mixing.

rotational motion
  جنبش ِ چرخشی   
jonbeš-e charkheshi

Fr.: mouvement de rotation   

Of a → rigid body, a motion in which there are always two points of the body which remain motionless.

rotational; → motion.

rotational period
  دوره‌ی ِ چرخش   
dowre-ye carxeš

Fr.: période de rotation   

rotation period.

rotational; → period.

rotational transition
  گذرش ِ چرخشی   
gozareš-e carxeši

Fr.: transition rotationnelle   

A slight change in the energy level of a molecule due to the rotation of its constituent atoms about their center of mass.

rotational; → transition.

rotational velocity
  تندای ِ چرخشی   
tondâ-ye catxeši

Fr.: vitesse de rotation   

The velocity of a → rotational motion; same as → angular velocity.

rotational; → velocity.

rotator
  چرخنده، چرخاننده   
carxandé (#), carxânandé (#)

Fr.: rotateur   

A device that rotates or causes rotation.

Agent noun from → rotate.

rotor
  چرخا   
carxâ (#)

Fr.: rotor   

A rotating part of an electrical apparatus, e.g. the armature of a generator, or of a mechanical device.
A system of several flat blades attached to a hub, which rotates either horizontally to give lift and thrust to a helicopter, or vertically to help control it.
Meteo.: The circulation of flow about a horizontal or nearly horizontal axis.

Short for rotator, → rotate, + → -or.

Carxâ agent noun of carxidan, → rotate.

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