On the lateral surface of the human brain, the central sulcus separates the frontal lobe from the parietal lobe. The lateral sulcus separates the frontal lobe from the temporal lobe. The frontal lobe bottom can be divided into a lateral, polar, orbital (above the orbit; also called basal or ventral), and medial part.
The age of an individual star can vary; they were all made at different times and have different life spans. Stars can range from a few million to a several billion years old. The oldest star yet discovered, HE 1523-0901, is an estimated 13.2 billion years old.
Computer models allow us to predict how old a star of that mass must be to be at that juncture of its life, and hence to estimate the age of the cluster. It is impossible to determine the age of a single star all by itself. The only real means we have to determine stellar ages is through the study of star clusters.