boreal forest: Taking taiga's temperature

eROSITA All-Sky Survey Takes the Local Hot Bubble's Temperature

eROSITA All-Sky Survey Takes the Local Hot Bubble's Temperature

Why doesn't CMB heat up Boomerang Nebula ? I was listening to this documentary and learned that Boomerang is cooler than CMB. How could that be? Is it constantly being cooled by escaping gas from its binary star that keeps temperature lower than CMB or is there something else at play here?