What might a significant deviation from the expected H to He ratio in a nebula suggest to astronomers?

Answer

Intensive stellar processing, such as fusion and enrichment, has occurred in that region

The ratio between hydrogen and helium acts as a fingerprint; any significant difference from the expected ratio implies that stellar evolution, where hydrogen is processed into helium, has significantly altered the local gas composition.

What might a significant deviation from the expected H to He ratio in a nebula suggest to astronomers?
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