An Etymological Dictionary of Astronomy and Astrophysics

English-French-Persian

فرهنگ ریشه‌شناختی اخترشناسی-اخترفیزیک



iron core
  مغزه‌ی ِ آهن  
maqze-ye âhan
Fr.: cœur de fer  
  1. Electromagnetism: A bar of → soft iron that passes through a coil and serves to increase the → inductance of the coil.

  2. The innermost part of some planets, such as Mercury, Venus, and Earth, which have a molten iron-rich core.

  3. The end point in the evolution of stars with a mass above ~ 10 → solar masses. Such a star evolves in several stages over millions of years during which various → thermonuclear reactions take place in the star core. Each stage results in a core composed of heavier elements. The process ends when → silicon burning produces a core of iron-nickel. Since iron has the maximum → binding energy per → nucleon, the → nuclear fusion cannot proceed further. The iron core shrinks and heats up. It is maintained against → gravitational collapse by → electron degeneracy pressure, but it continues to grow as Si burning adds more iron. When the core reaches its → Chandrasekhar limit, it becomes unstable and undergoes the → core collapse.

See also:iron; → core.