مغزهی ِ آهن
Fr.: cœur de fer
1) Electromagnetism: A bar of → soft iron that passes
through a coil and serves to increase the → inductance of
2) The innermost part of some planets, such as Mercury, Venus, and Earth, which have a molten
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.
→ iron; → core.