Inferring Stellar Lifetimes: Scientists Must Often Draw on a Variety

Inferring stellar lifetimes: Scientists must often draw on a variety of concepts to develop new understanding. Take, for example, the inferred lifetimes of stars. What two properties must be precisely measured in order to estimate the lifetime? Outline the set of observations that must be made in order to determine those properties. Then discuss the fundamental physics that must be understood to relate these to the rate at which hydrogen is converted to helium in the stellar core, and to determine the amount of hydrogen available in the core.