Quote:
Originally Posted by Merlin66
The "core" WR star, HD 50896 is classified as a WN4-s star. Normally these Nitrogen WR have no Oxygen emissions, basically Helium and Nitrogen. The strong HeII at 6560A is commonly mis-identified as Ha. The strong line at 4686A contributes to a green colour....
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Ken, for us mice, does your comment relate to the Gourd Nebula (the great vastness of Murray's image, or only the spectroscopy of the central star?
The spectrum of the star may have little to do with either the chemical composition or the spectrum of the nebula.
I am thinking that the nebula itself comprises shocked material, some of which contains hydrogen and oxygen previously shed by the star, and some of which was pre-existing background material. Hard UV from the central star would produce both H-alpha and OIII emission in this composite material. Even shock energy could contribute to broadening the acceptable excitation wavelengths n the nebula.
Cheers,
Mike