Spectroscopy of Stars: Electrons in Plasma

Click For Summary

Discussion Overview

The discussion revolves around the application of spectroscopy in determining the elemental composition of stars, particularly focusing on the behavior of electrons in a plasma state versus bound states in atomic structures. It explores the implications of these states for the interpretation of spectral lines.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants note that spectroscopy allows astronomers to identify elements in stars through characteristic spectral lines formed by electron transitions between orbital energy levels.
  • Others argue that since stars exist in a plasma state, the rapid movement of electrons and nuclei complicates the formation of stable electron orbits, raising questions about the validity of spectroscopy in this context.
  • It is mentioned that the outer layers of stars can be cool enough for plasma to recombine into atoms, suggesting that spectroscopy may only provide information about these upper layers.
  • One participant points out that stars produce both emission and absorption spectral lines, indicating a complexity in the spectral analysis.
  • Another contribution highlights that spectral lines can still be observed even if electrons are only temporarily bound to nuclei, as a small fraction of atoms can absorb light despite being in a highly ionized state.

Areas of Agreement / Disagreement

Participants express differing views on the nature of stars and the implications for spectroscopy. While some agree on the presence of non-plasma states in outer layers, others emphasize the challenges posed by the plasma state, leading to an unresolved discussion regarding the overall applicability of spectroscopy in stellar analysis.

Contextual Notes

The discussion reflects limitations in understanding the behavior of electrons in different states and the conditions under which spectroscopy can be effectively applied. There are unresolved questions about the extent to which plasma states affect spectral line formation.

Sophrosyne
Messages
128
Reaction score
21
Astronomers can determine the presence various elements in a star through spectroscopy of the incoming light from that star. The characteristic spectral lines of each element are formed by electrons transitioning between the various orbital energy levels around the nucleus of their atom.

But stars are in a plasma state. The electrons and nuclei are moving around too fast for stable electron orbits to develop. So how can you do spectroscopy on a star if you don't have electrons in orbits around nuclei?
 
Astronomy news on Phys.org
Stars are not all plasma. The outer layers of stars are cool enough for the plasma to recombine into atoms. Spectroscopy tells you about the composition of those upper layers only.
 
Bandersnatch said:
Stars are not all plasma. The outer layers of stars are cool enough for the plasma to recombine into atoms. Spectroscopy tells you about the composition of those upper layers only.

This makes sense. Thanks.
 
What's more, you can get spectral lines even if the electrons are only bound to the nuclei for very short times. Even a highly ionized gas will always have a tiny fraction of its atoms in a state that can absorb light for a short time. Also, many types of nuclei have a large positive charge, so it is very difficult to strip all their electrons, even if the hydrogen are largely stripped.
 

Similar threads

  • · Replies 0 ·
Replies
0
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 60 ·
3
Replies
60
Views
12K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 9 ·
Replies
9
Views
5K
  • · Replies 4 ·
Replies
4
Views
3K