※ 引述《JCMaxwell (馬克先生~)》之銘言： : 1. : 【題目】 : 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 相較於 Stellar nucleosynthesis 和 Explosive nucleosynthesis 對地球上的元素有什麼影響 : 【瓶頸】 查過 Carroll & Ostile 的書，和資料了，還是找不出哪裡不正確... : 2. : 【題目】 : 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. : 【瓶頸】 這是一題反證題，planetary nebula 很明顯不是"ring" ，可是題目有說不能 : 單純說哪裡不對，要用反證法說如果XX成立，則...，實在沒有頭緒 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. : 【題目】 : 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. : 【瓶頸】這題也知道不是"below",可是怎麼反證又難倒小弟了... : 因為很少寫關係，實在不太會反證法，也許是太習慣只有算式的題目了吧...想想真是 : 慚愧 : 不好意思，問題有點多，麻煩各位前輩了，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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