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I understand why stars have absorption lines, but I am not entirely sure why they don't have emission lines. Wouldn't the gas on the surface of the stars be hot enough to at least give off some emission?

nocappp
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    Consider the scale of kT vs an emission line width, much less the entire width of the visible spectrum. 300K is about 23meV, so 3000K is almost a quarter of an eV, so the sun as a blackbody at ~5700K smears emission out over nearly half an eV. – Jon Custer Mar 01 '21 at 04:09
  • I found the answer to that one a little confusing, but I think the top comment here answers my question. Thanks! – nocappp Mar 01 '21 at 04:55
  • @JonCuster emission lines are seen from the Sun and from plasma at temperatures $10^4-10^6$ K. The fractional width of a spectral line is given by $\sim v/c \simeq \sqrt {kT/mc^2}$, not what you suggest. – ProfRob Mar 01 '21 at 08:16

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