Which stars typically illuminate and ionize the gas within a star-forming diffuse nebula?

Answer

Newly formed, extremely hot, massive stars, often O or B type.

These young, brilliant stars radiate enormous amounts of energetic ultraviolet light required to ionize the vast hydrogen clouds around them.

Which stars typically illuminate and ionize the gas within a star-forming diffuse nebula?

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The 5 Types of Nebulae | Star Gazers - YouTube

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