How do Wolf-Rayet stars expose ultra-hot core material typically hotter than stable O-stars?

Answer

By shedding their cooler outer layers through powerful stellar winds

Wolf-Rayet stars are evolved, massive stars that have lost their outer hydrogen envelopes, exposing the ultra-hot core material which is fusing helium or heavier elements.

How do Wolf-Rayet stars expose ultra-hot core material typically hotter than stable O-stars?
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