Stars have a predictable way of aging.It is mostly dependent on the mass of the star because this determines how much fuel and by how how much gravity the star can generate to keep it together. For example or star the sun will keep burning hydrogen for the next 4.5 billion years. Then it will get larger and larger staying the same size for shorter and shorter periods. The last stage the sun will throw off the outer layers forming a planetary nebula.
One Class of stars that do not follow their predictable model are stars called blue stragglers. A new study of these stars by Dr. Gosnell my of figured out way these stars do no follow this model. These stars orbit stars that reach the red giant phase of life. The outer layers of the red giants is tenuously held to the star. The neighboring star sucks these outer layers onto itself gaining mass and fuel leaving the first star a white dwarf. Thus the star increases it mass and burns hotter and bluer. These stars are found in globular clusters. Most of the stars tend to be in the later stages of life while these stars seem be behind in development.