Answer: Blue Stragglers
In 1953, astronomer Allan Sandage was measuring the intensity of stars in the globular Messier 3 star cluster (if you’re a fan of constellations, this star cluster is located in the northern constellation Canes Venatici). Sandage observed a rather peculiar occurrence right in our own celestial backyard, the Milky Way: stars that appeared far, far, younger than their nearest celestial neighbors. How could these few rogue stars appear so blue (an indicator of a higher temperature and hydrogen content, and thus younger age) compared to their neighbors, who presumably formed at the same time?
These stars maintain their youthful appearance much in the same way as the vampires of human legend: by siphoning the energy of their companions. The two most viable theories as to how this happens are that the stars are mated as binary stars and one is slowly feeding off the other, or that they are current or former binary stars that are in the process of merging or have already done so. Either way, it’s apparent that there is some sort of transfer from some stars to nearby stars. In dense regions of clusters, especially in the cores of globular clusters, there are dozens of these blue stragglers, quietly pulling the hydrogen right out of their neighbors and, in the process, extending their own lifespans at the expense of the stars they feed on.