This reaction produces 640 gigajoules per kilogram of material, and is most important at temperatures below 15 million Kelvin.  The average time required for the first step is, on average, approximately 14 billion years, while the second and third steps take 6 seconds and 1 million years, respectively.  In the Sun, however,
This reaction produces 640 gigajoules per kilogram of material, and is most important at temperatures below 15 million Kelvin.  The average time required for the first step is, on average, approximately 14 billion years, while the second and third steps take 6 seconds and 1 million years, respectively.  In the Sun, however, 600 million tons of hydrogen are still reacted every second using this mechanism.  FTP, name this set of reactions responsible for producing energy in average-size stars, so named because it starts with the reaction of two hydrogen nuclei.
This reaction produces 640 gigajoules per kilogram of material, and is most important at temperatures below 15 million Kelvin.  
proton-proton cycle