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Earth and Space Sciences · 术语表

什么是 Metallicity？

Definition 30.2 University Earth and Space Sciences — Year 3 · 第 30 章 — Where the Elements Come From

The metallicity of a star or of a gas is its content of elements heavier than helium, called metals in astronomy whatever their chemistry: as a mass fraction ZZ, or, as it is usually measured, as the iron abundance relative to the Sun, [Fe/H][\mathrm{Fe/H}]. A star with [Fe/H]=−1[\mathrm{Fe/H}] = -1 has a tenth of the Sun’s iron per hydrogen atom.

The Sun against the CI chondrites: each point is one element with both values (Asplund, Amarsi and Grevesse, 2021; the meteoritic scale is fixed so that silicon agrees). The dashed line is equality. Black dots: the 58 elements that agree. Squares: hydrogen, helium, carbon, nitrogen, oxygen and the noble gases, which the meteorites did not keep. Triangle: lithium, destroyed in the Sun.
The Sun against the CI chondrites: each point is one element with both values (Asplund, Amarsi and Grevesse, 2021; the meteoritic scale is fixed so that silicon agrees). The dashed line is equality. Black dots: the 58 elements that agree. Squares: hydrogen, helium, carbon, nitrogen, oxygen and the noble gases, which the meteorites did not keep. Triangle: lithium, destroyed in the Sun.
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