| 单词 | metal abundance |
| 释义 | > as lemmasmetal abundance g. Astronomy. In a star or its spectrum: any chemical element other than helium or hydrogen. Frequently attributive, esp. in metal abundance. ΚΠ 1973 M. Harwitt Astrophysical Concepts i. 24 This low..metal abundance—in this context the word ‘metal’ denotes any atom heavier than helium—is a real puzzle. 1975 Nature 18 Sept. 184/3 As any galaxy ages, the proportion of metals (by which astronomers mean anything except hydrogen and helium) in its stars increases through nucleosynthesis. 1987 C. Jaschek & M. Jaschek Classification Stars i. 22 Stellar interior specialists use ‘metals’ to designate any element other than hydrogen and helium, and in consequence ‘metal abundance’ implies all elements other than the first two. For spectroscopists this is very misleading, because they use the word in the chemical sense. On the other hand photometrists, who observe combined effects of all lines (i.e. without distinguishing the different elements) often use this word (metal abundance), in which case it may also include the effect of the hydrogen lines. 1992 S. P. Maran Astron. & Astrophysics Encycl. 236/2 There are some galaxies..that show incredibly strong star formation activity but have metal abundances so low as to suggest that they are perhaps now experiencing their first burst. < as lemmas |
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