With the aid of a powerful instrument, researchers have detected subatomic particles produced by fusion reactions at the very core of the sun.

The particles are neutrinos, and the ones detected in this study are low in energy but abundant in number, said Andrea P. Pocar, a physicist at the University of Massachusetts, Amherst. The neutrinos are formed by a fusion reaction between two protons at the core of the sun; they travel to Earth in just eight minutes (almost at the speed of light).

“Previous experiments had measured neutrinos from the sun, but those neutrinos are present in very low numbers,” Dr. Pocar said. “These make up about 90 percent of the total neutrinos from the sun.”

Dr. Pocar and his colleagues, a group of more than 90 physicists from around the world, published their findings in the current issue of the journal Nature.