An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 10 Search : circumstellar
circumstellar
  پیراستاره‌ای   
pirâsetâreyi

Fr.: circumstellaire   

Surrounding or occurring around a star.

Circumstellar, from → circum- + → stellar.

circumstellar disk
  گرده‌ی ِ پیراستاره‌ای   
gerde-ye pirâsetâreyi

Fr.: disque circumstellaire   

Any concentration of material in the form of a disk orbiting around a star. → accretion disk; → protoplanetary disk.

circumstellar; → disk.

circumstellar dust
  غبار ِ پیراستاره‌ای   
qobâr-e pirâsetâreyi

Fr.: poussière circumstellaire   

Interstellar → dust grains localized around various types of stars, such as → asymptotic giant branch stars. Circumstellar dust occurs in the form of a spherical shell or a disk and is at the origin of an → infrared excess for the central star. See also → circumstellar matter.

circumstellar; → dust.

circumstellar envelope
  پوشه‌ی ِ پیراستاره‌ای   
puše-ye pirâsetâre-yi

Fr.: enveloppe circumstellaire   

A very extensive envelope of cold gaseous materials surrounding evolved cool stars, notably → red giants, → red supergiants (→ Mira variables), or → asymptotic giant branch stars. The typical size of such envelopes is several thousands times that of the stellar radius and their temperature ranges from 1000 to10 K. Circumstellar envelopes result from mass loss from the central star (10-7 to 10-4solar masses per year) and expand with moderate velocities (10 to 15 km sec-1). The low temperature of the envelope is at the origin of the formation of molecules, which in certain conditions provide → maser emission (H2O, OH, SiO). Similarly, dust grains form in the envelope produce an → infrared excess emission.

circumstellar; → envelope.

circumstellar environment
  پرگیر ِ پیراستاره‌ای   
pargir-e pirâsetâre-yi

Fr.: environnement circumstellaire   

The circumstances or physical conditions related to the immediate surroundings of a star.

circumstellar; → environment.

circumstellar habitable zone
  زنار ِ زیست پذیر ِ پیراستاره‌ای   
zonâr-e zistpazir-e pirâsetâreyi

Fr.: zone habitable circumstellaire   

A zone around a star within which a planet can have temperatures that permit liquid water, depending on the luminosity of the star and the distance of the planet from it.

circumstellar; → habitable zone.

circumstellar maser
  میزر ِ پیراستاره‌ای   
meyzer-e pirâsetâreyi

Fr.: maser circumstellaire   

Maser emission from molecules in the circumstellar envelopes of → red giants, and also from regions around → protostars.

circumstellar; → maser.

circumstellar matter
  ماده‌ی ِ پیراستاره‌ای   
madde-ye pirâsetâreyi

Fr.: matière circumstellaire   

Dust, gas and plasma around stars, generally present in the form of stellar winds or nebulae ejected by the stars.

circumstellar; → matter.

circumstellar outflow
  استچان ِ پیراستاره‌ای   
ostacân-e pirâsetâreyi

Fr.: flot circumstellaire   

A stream of matter into the interstellar medium from a central star.

circumstellar; → outflow.

circumstellar shell
  پوسته‌ی ِ پیراستاره‌ای   
puste-ye pirâsetâreyi

Fr.: coquille circumstellaire   

A shell of dust, molecules, and neutral gas around an evolved star resulting from an intensive mass loss phase, such as the asymptotic giant branch phase for low- and intermediate mass stars and LBVs or supernovae for massive stars.

circumstellar; → shell.