Discussion Overview
The discussion centers around the emission spectra of nebulae, specifically why they predominantly exhibit emissions from Hydrogen (alpha), Sulfur II, and Oxygen III. Participants explore the implications of these emissions in relation to the elements present in nebulae, particularly in the context of astrophotography and the fusion processes of stars.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant expresses confusion about why nebulae primarily emit Hydrogen, Sulfur, and Oxygen, questioning if other elements should also be present based on stellar fusion history.
- Another participant challenges the claim of restricted emissions, asking for references and noting that nebulae have a continuous spectrum and come in various forms.
- A participant suggests that the focus on H, S, and O in astrophotography may be due to these elements being the most visible when excited by radiation from nearby stars.
- One participant cites a search indicating that most nebulae are approximately 90% Hydrogen, with Sulfur and Oxygen making up most of the remaining 10%, leading to their prominence in emission lines.
- Another participant mentions that only about 10% of a star's Hydrogen is fused during the main sequence and questions the lack of Helium emissions, attributing it to visibility issues in the spectrum.
- A clarification is made that planetary nebulae originate from dissipated red giants rather than supernovae, which may limit the variety of elements present.
Areas of Agreement / Disagreement
Participants express differing views on the reasons for the prominence of H, S, and O emissions in nebulae. While some propose explanations related to the visibility of these elements, others question the completeness of this perspective, indicating that multiple competing views remain unresolved.
Contextual Notes
Participants note the limitations in understanding the emission spectra, including the potential scarcity of other elements and the dependence on the excitation conditions in nebulae.
