The phrase "active star" refers to a star that is continuously giving off energy and undergoing various processes, such as nuclear fusion. It means that the star is vibrant, lively, and not dormant or inactive. Full definition
Actually, there are some galaxies with active star formation at the central part of the cluster. (sciencedaily.com)
But up until now it has been difficult to determine the positions of active star forming galaxies with enough precision to actually test this prediction. (sciencedaily.com)
That explains why radio astronomers have found more complex molecules in the warmer, more active star - birthing regions of dust clouds than in the colder, darker areas. (discovermagazine.com)