| 释义 |
metallicity rare.|mɛtəˈlɪsɪtɪ|
[f. metallic a. + -ity.]
The quality of being metallic.
1831Amer. Jrnl. Sci. XIX. 188 The..method which Dr. Wollaston employed to discover metallic titanium in the scoria of iron, and to prove the metallicity of the small crystals of titanium. 1883Encycl. Brit. XVI. 32/1 The alchemists..held that mercury..enters into the composition of all metals, and is the very cause of their metallicity.
Add:2. Astron. The relative abundance in a celestial object of elements heavier than helium.
In practice the relative abundance of iron relative to hydrogen, as inferred from their line strengths, is usually taken as a measure of this.
1969Astron. & Astrophysics II. 226/2 How can we explain the very high metallicity of the field star τ UMa, and the very different chemical composition amongst the stars of one and the same cluster such as the Hyades? 1980Astrophysical Jrnl. CCXLII. 242/1 The age-metallicity relation (AMR) for the disk is an important constraint on theoretical models of galactic evolution. 1989R. A. Meyers Encycl. Astron. & Astrophysics 653/2 The usual means of quoting metallicity for these clusters..is in terms of the Fe/H ratio. This is normally quoted as a differential measure relative to the sun, as [Fe/H] = log(Fe/H) - log(Fe/H){sun} . 1992Astronomy May 32/2 Another study of LSB galaxies shows they have very low metallicities, meaning they are made almost exclusively of hydrogen and helium. |