https://www.science20.com/news_articles/three_generations_stars_whirlpool_galaxy-128468
Three Generations Of Stars In The Whirlpool Galaxy | Science 2.0
NGC 5194, also known as M51, the Whirlpool Galaxy, is one of the most spectacular examples of a spiral galaxy, with two spiral arms curling into one another in...
generations of starsin the whirlpoolscience 2three
https://esahubble.org/images/heic0708a/zoomable/
Multiple generations of stars in a globular cluster
generations of starsmultipleglobularcluster