Mass segregation (astronomy)

Mass segregation is a process in astronomy where some stars or other heavenly bodies (like planets or black holes) group together depending on how much mass (how heavy they are) they have. When this happens, stars with more mass move to the centre of the group, while the stars with less mass end up on the edges. Think of it like a big group of stars sitting in a circle - the stars with more mass move closer to the middle, while the stars with less mass stay closer to the edge.