The sun is a type G2V star. By mass, it is composed of 72% hydrogen, 26% helium and 2% trace elements of oxygen, carbon, neon, nitrogen, magnesium, iron, and silicon.<ref>[http://www.nasa.gov/worldbook/sun_worldbook.html World Book Encyclopedia @ NASA]</ref> | The sun is a type G2V star. By mass, it is composed of 72% hydrogen, 26% helium and 2% trace elements of oxygen, carbon, neon, nitrogen, magnesium, iron, and silicon.<ref>[http://www.nasa.gov/worldbook/sun_worldbook.html World Book Encyclopedia @ NASA]</ref> |