Jan. 30 (UPI) -- Scientists have traced the grains that coalesced to form the planets in our solar system. They were formed by Asymptotic Giant Branch stars, or AGB stars.
AGB stars are six times larger than our sun and thousands of times brighter. These aging red dwarfs shed their outer layers as their inner cores expand. The expelled outer layers become interstellar clouds of gas and dust -- material which forms new stars as well as protoplanetary disks.