※ 引述《JCMaxwell (马克先生~)》之铭言： : 1. : 【题目】 : All the metals made by a star through nuclear syntheses will be : trapped in the core by its own strong gravitational potential. : We will never see absorption lines of metals in any stellar spectra. However, the spectra of the Sun shows absorption lines of metals. This means not all the metals made by a star through nuclear syntheses are trapped in the core. : All the metals (A > 4) on the Earth should be made at the moment when the : Universe was created and have nothing to do with what stars are doing. 可能要找 Big Bang nucleosynthesis 相较於 Stellar nucleosynthesis 和 Explosive nucleosynthesis 对地球上的元素有什麽影响 : 【瓶颈】 查过 Carroll & Ostile 的书，和资料了，还是找不出哪里不正确... : 2. : 【题目】 : Speaking of a similar phenomenon, a fantastic planetary nebula (PN) appears : as a glowing circular ring around its central relic star, i.e. a white : dwarf. : PNe should be expanding "rings" of hot gas in the space. : 【瓶颈】 这是一题反证题，planetary nebula 很明显不是"ring" ，可是题目有说不能 : 单纯说哪里不对，要用反证法说如果XX成立，则...，实在没有头绪 If a planetary nebula is a single glowing circular ring round its central relic star, we should not see any light coming from the space between the star and the ring. However, Hubble data of Messier 57 shows light coming from the space between the star and the ring. Therefore, a planetary nebula is more than a single glowing circular ring. : 3. : 【题目】 : I know those dark lines in the solar (or stellar) spectrum. They are : absorption lines caused by molecules above the photosphere, whose emission : is characterized by a blackbody radiation at Te = 5777 K. : Similarly,emission lines in the solar spectrum must come from : molecules ""below"" the photosphere. : 【瓶颈】这题也知道不是"below",可是怎麽反证又难倒小弟了... : 因为很少写关系，实在不太会反证法，也许是太习惯只有算式的题目了吧...想想真是 : 惭愧 : 不好意思，问题有点多，麻烦各位前辈了，感恩! By definition, the photosphere emits most of the light coming from a star. If emission lines in the solar spectrum come from molecules below the photosphere but absorption lines come from molecules above the photosphere, we should see weaker strength in emission lines compared to absorption lines. However, for each molecule we see similar expected strength in absorption and emission lines. Therefore, emission lines in the solar spectrum must also come from moleculars above the photosphere. --

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