This is the dark nebula. The smaller blue portion of the Trifid is caused by dust dispersing the blue light of nearby young hot stars. This is the reflection nebula. You may have already guessed, the Trifid is another stellar nursery. Chacoan priests routinely awoke to greet the sun.
Stars have several ways of dying.
One of the least common paths is when stars supernova, or blow themselves apart. The threshold mass for a traditional supernova event is about nine times that of the sun. Stars from several solar masses to the least massive stars in our universe will go through an instability stage near the very ends of their lives. As a red giant star, they will rapidly fluctuate in brightness and energy production, eventually shedding a considerable percentage of their matter into space. This is what has happened in the case of the Dumbbell.