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: 23 Search : main
terminal age main sequence (TAMS)
  رشته‌ی ِ فریست با سن ِ پایانی   
rešte-ye farist bâ senn-e pâyâni

Fr.: séquence principale d'âge terminal   

The locus of stars on the → Hertzsprung-Russell diagram that are at the point of exhausting hydrogen in their cores. TAMS forms the upper luminosity boundary of the → main sequence strip. See also → zero age main sequence (ZAMS).

terminal; → age; → main; → sequence.

upper main sequence
  رشته‌ی ِ فریست ِ زبرین   
rešte-ye farist-e zabarin

Fr.: séquence principale supérieure   

A → main sequence star with a mass above 1.5 Msun. Upper main sequence stars have high central temperatures so that they produce their energy through the → CNO cycle. The outward energy flux is very high and therefore this flux cannot be maintained by → radiative transfer. Thus, upper main sequence stars have → convective cores. Outside the core, there is a → radiative zone. The mass of the convective core gradually diminishes as the hydrogen is consumed. The surface hydrogen is fully ionized and the → opacity is due to → electron scattering The opacity due to electron scattering.

upper; → main; → sequence.

zero age main sequence (ZAMS)
  رشته‌ی ِ فریست با سن ِ صفر   
rešte-ye farist bâ senn-e sefr

Fr.: séquence principale d'âge zéro   

The position on the → Hertzsprung-Russell diagram for newborn stars which have just started → hydrogen burning in their cores. The ZAMS forms the lower luminosity boundary of of the → main sequence strip. See also → terminal age main sequence (TAMS).

zero; → age; → main sequence.

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