AS102 Study Guide - Final Guide: Main Sequence
Document Summary
Because starlight comes from the fusion furnace existing in the interior of each star, eventually stars use up all of the hydrogen needed for fusing (and producing starlight). When this happens, stars die and we will examine the death part of a star"s lifecycle shortly. However, for most of the star"s life it survives by fusing hydrogen into helium, generating light in the process. The lifetime of a star depends on the initial mass of the star. Contrary to intuition, the more massive a star is the shorter its lifetime!! Larger stars have higher gravity that results in a higher interior temperature. A higher temperature means that the fusion rate is greater so the star uses up its h supply faster. Our sun has a main sequence lifetime of about 10 billion years. A 30msun star has a lifetime of about a million years (a short time from a cosmological perspective another reason why there are relatively few massive stars).
