| 词汇 | metallicity |
| 释义 | metallicity noun[ C or U ] physics specializeduk /ˌmet.əlˈɪ.sə.ti/ us /ˌmet̬.əlˈɪ.sə.t̬i/ the amount of material that is not helium or hydrogen in a star, planet, etc.: 金属量（星体内除氢和氦元素外其他化学元素的比例） 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。 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. Physics: the state of matter absorbency acidic allotropic allotropy compressible crystalline e-liquid fluidity impervious melted polyunsaturated rarefy reflective rustily rusty scaly self-healing sloppily sloppiness sloppy Examples of metallicitymetallicity For example, the radial galactic metallicity gradient determines isotope concentrations, silica and magnesium concentrations, etc., all of which are important for forming habitable planetary systems. The bar will hence be able to relocate stars, and stars with low or high metallicity could be found far away from their original orbits. For example, until sufficient metallicity has developed by the stellar burning of light elements, terrestrial type planets will not form. This occurs more rapidly in stars that are more massive and lower in metallicity. Thus, high metallicity stars could be found in all parts of a barred galaxy. In particular, the association of planet size and occurrence frequency with stellar mass and metallicity will be investigated. This rules out the outer parts of the disc where the metallicity is low due to slow star formation. Observations of extrasolar planetary systems indicate that the presence of giant extrasolar planets at small distances from their host stars is strongly correlated with high metallicity of the host stars. Metallicity tends to play a large role in the formation of planets, determining if they form, and what kind of planet they will form. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In practice, corrections are required to account for variations in age or metallicity from galaxy to galaxy. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The unit often used for metallicity is the dex which is a (now-deprecated) contraction of decimal exponent. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Stars of higher mass and metallicity tend to have more numerous and more massive planets. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The lower metallicity decreases the opacity of their outer layers and decreases the radiation pressure, resulting in a smaller, hotter star for a given mass. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The explanation of their underluminosity lies in their low metallicity: these stars are unenriched in elements heavier than helium. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. A moving group is distinguished by its members having about the same age, composition (or metallicity) and motion through space. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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