What is the zero age main sequence of a stars life?
zero-age main sequence (ZAMS) The diagonal strip on the Hertzsprung–Russell diagram occupied by stars that have just begun to convert hydrogen to helium in their cores. As this conversion proceeds, stars become slightly redder and more luminous, so they move upwards and to the right on the HR diagram. As a result, the main sequence is a broad band that is displaced slightly from this zero-age strip.
