An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 435 Search : ad
radiative capture
  گیراُفت ِ تابشی، گیر‌اندازی ِ ~   
gir-oft-e tâbeši, gir-andâzi-ye ~

Fr.: capture radiative   

Capture of a free electron by an ion with the subsequent emission of photons; also called → radiative recombination.

radiative; → capture.

radiative collision
  همکوبش ِ تابشی   
hamkubeš-e tâbeši

Fr.: collision radiative   

A collision between charged particles in which part of the kinetic energy is converted into electromagnetic radiation.

radiative; → collision.

radiative cooling
  سردش ِ تابشی   
serdeš-e tâbeši

Fr.: refroidissement radiatif   

The process by which temperature decreases due to an excess of emitted radiation over absorbed radiation.

radiative; → cooling.

radiative decay
  تباهی ِ تابشی   
tabâhi-ye tâbeši

Fr.: désexcitation radiative   

The process when the energy difference between the excited and non excited states of an atom is taken away by radiation.

radiative; → decay.

radiative diffusion
  پخش ِ تابشی   
paxš-e tâbeši

Fr.: diffusion radiative   

A process of → radiative transfer in which photons are repeatedly absorbed and re-emitted by matter particles.

radiative; → diffusion.

radiative envelope
  پوشه‌ی ِ تابشی   
puše-ye tâbeši

Fr.: envelope radiative   

A → radiative zone occupying the outer parts of a star.

radiative; → envelope.

radiative equilibrium
  ترازمندی ِ تابشی   
tarâzmandi-ye tâbeši

Fr.: équilibre radiatif   

The balance between radiative emission and radiative absorption in a specified system.

radiative; → equilibrium.

radiative feedback
  بازخورد ِ تابشی   
bâzxord-e tâbeši

Fr.: rétroaction radiative   

The radiative energy put back to the environment through an astrophysical process. For example, in the process of → star formation  → accretion disks form around → protostars. The material in the disk spirals inward and on to the protostar, provided that there is an efficient mechanism to redistribute → angular momentum outward in the disk. During this process → gravitational energy is transformed into radiation due to → viscous dissipation in the disk and at the → accretion shock around the protostar. This radiation heats the region around the protostar and may → suppress subsequent → fragmentation and further star formation. Thus, radiative feedback plays a critical role in regulating the stellar → initial mass function.

radiative; → feedback.

radiative flux
  شار ِ تابشی   
šârr-e tâbeši

Fr.: flux radiatif   

The radiative energy per unit time and unit area.

radiative; → flux.

radiative heating
  گرمش ِ تابشی   
garmeš-e tâbeši

Fr.: chauffage radiatif   

The process by which temperature increases due to an excess of absorbed radiation over emitted radiation.

radiative; → heating.

radiative levitation
  بالاشد ِ تابشی   
bâlâšod tâbeši

Fr.: lévitation radiative   

A physical process occurring in → stellar atmospheres whereby → radiation pressure selectively pushes certain → chemical elements outward, leading to an atmospheric overabundance of such elements. See also → gravitational settling.

radiative; → levitation.

radiative phase
  فاز ِ تابشی   
fâz-e tâbeši

Fr.: phase radiative   

For a → supernova remnant (SNR), same as the → snowplow phase.

radiative; → phase.

radiative process
  فراروند ِ تابشی   
farâravand-e tâbeši

Fr.: processus radiatif   

An process in which an excited state loses its absorbed energy by emission of radiation. → non-radiative process.

radiative; → process.

radiative recombination
  بازمیازش ِ تابشی   
bâzmiyâzeš-e tâbeši

Fr.: recombinaison radiative   

The process by which an ionized atom binds a free electron in a → plasma to produce a new atomic state with the subsequent radiation of photons.

radiative; → recombination.

radiative shock
  تش ِ تابشی، شوک ِ ~   
toš-e tâbeši, šok-e ~

Fr.: choc radiatif   

A → shock wave in which the → time-scale for → cooling is much shorter than the appropriate → dynamical or → evolutionary time-scale of the system that drives the shock. Radiative shock waves are believed to play a key role in a variety of different astrophysical environments, including → magnetic cataclysmic variables, → jets from → young stellar objects, → accretion in → T Tauri stars, → colliding stellar winds, and → supernova remnants.

radiative; → shock.

radiative transfer
  تراواژ ِ تابش، ~ تابشی   
tarâvâž-e tâbeš, ~ tâbeši

Fr.: transfer radiatif, ~ de rayonnement   

The process by which the → electromagnetic radiation passes through a medium that may contain any combination of → scatterers, → absorbers, and → emitters.

radiative; → transfer.

radiative transfer equation
  هموگش ِ تراوَژ ِ تابش   
hamugeš-e tarâvaž-e tâbeš

Fr.: équation de transfer radiatif, ~ ~ de rayonnement   

The equation that describes the → radiative transfer. It states that the → specific intensity of radiation Iσ during its propagation in a medium is subject to losses due to → extinction and to → gains due to → emission: dIσ/dx = - μσ . Iσ + ρ . jσ, where x is the coordinate along the → optical path, μσ is the → extinction coefficient, ρ is the mass → density, and jσ is the → emission coefficient per unit mass.

radiative; → transfer; → equation.

radiative transition
  گذرش ِ تابشی   
gozareš-e tâbeši

Fr.: transition radiative   

A transition between two states of an atomic or molecular entity, the energy difference being emitted or absorbed as photons.

radiative; → transition.

radiative zone
  زنار ِ تابشی   
zonâr-e tâbeši

Fr.: zone radiative   

The region of a star in which the energy generated by → nuclear fusion in the core is transferred outward by → electromagnetic radiation and not by → convection. Such zones occur in the interior of low-mass stars, like the Sun, and the envelopes of → massive star. The radiative zone of the Sun starts at the edge of the core of the Sun, about 0.2 solar radii, and extends up to about 0.7 radii, just below the → convective zone.

radiative; → zone.

radiatively driven wind
  باد ِ تابشی   
bâd-e tâbeši

Fr.: vent radiatif   

Same as → radiation-driven wind

radiative; → drive; → wind.

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