What element with a high vapor point the emits to least light or radiation when heated to its vapor pressure point in a vacuum?

Ideally I would like to know in 0 gravity and 0 pressure which elements can be get the hottest around the sun before the vapor pressure point is reached and/or emit the least black body radiation when hot.


  • 7
    $\begingroup$ The black body radiation from all elements and compounds is the same. $\endgroup$
    – Karl
    Apr 12, 2019 at 20:33
  • 1
    $\begingroup$ i suppose an isolated proton wouldn't $\endgroup$
    – A.K.
    Apr 13, 2019 at 4:00
  • $\begingroup$ As for A.K. comment: your question should be what ensemble of matter does not emit EM radiation (or Vis, depending on your exact meaning) when hot? Then the answer is in the comment by Karl. (Dark matter not considered as for no chemistry can be done ;) $\endgroup$
    – Alchimista
    Apr 13, 2019 at 8:28
  • $\begingroup$ @Alchimista is this better? $\endgroup$
    – Muze
    Apr 13, 2019 at 15:52
  • $\begingroup$ Say substance, so you get rid of the fact that atoms/molecules can't have a T and a vapour pressure. Hot atoms are at best moving faster. But you got an answer so.... Referring to a limit made the Q interesting. $\endgroup$
    – Alchimista
    Apr 14, 2019 at 7:20

1 Answer 1


Technically, a smooth or molten, unoxidized metal surface (regardless of chemistry) makes a good candidate. This thesis from Auburn University reports the emissivities of both oxidized and unoxidized metals at temperatures typically encountered in industrial processes; note the low values for all the unoxidized metals studied in the IR range where most radiation is given off.

  • $\begingroup$ Yes but mecury has a low evaporation point. $\endgroup$
    – Muze
    Apr 13, 2019 at 19:10
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    $\begingroup$ @Muze — But the state does not matter in emitting electromagnetic waves! $\endgroup$
    – SteffX
    Jul 10, 2019 at 15:57
  • $\begingroup$ @Steffi can you please explain more in an answer for a Layman like myself can understand. $\endgroup$
    – Muze
    Jul 10, 2019 at 21:28
  • $\begingroup$ Will anyone please tell me what is wrong with this answer? $\endgroup$ Jul 10, 2019 at 23:27
  • 1
    $\begingroup$ I thought maybe @SteffX would have went more into detail with an answer but he didn't. I think your answer is good. Tks $\endgroup$
    – Muze
    Jul 12, 2019 at 13:18

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