The formation of our solar system was a messy affair. Most of the material that existed before its formation—material formed around other, long-dead stars—was vaporized, then recondensed into new materials. But some grains of that material, formed before the sun’s birth, still persist.
Click here for original story, Ancient micrometeoroids carried specks of stardust, water to asteroid 4 Vesta
Source: Phys.org