metallicity
noun [ C or U ] physics specialized uk/ˌmet.əlˈɪ.sə.ti/ us/ˌmet̬.əlˈɪ.sə.t̬i/
金属量（星体内除氢和氦元素外其他化学元素的比例）
the amount of material that is not helium or hydrogen in a star, planet, etc.
20 to 30% of sun-like stars with large metallicities are known to have planets. 已知有20%到30%的具有大金属丰度的类太阳恒星都有自己的行星。
Compared to the Sun, 47 Tucanae has less than a third the metallicity. 与太阳相比，杜鹃座47的金属丰度不到1/3。
- More examples
- The greater a star's metallicity, the better its chances to have planets.
- If the metallicity is too low, there is not enough material to build Earth-like planets.
- The process can make planets with enriched metallicities as seen in our own solar system.