How do we know which asteroid a meteorite came from?
Usually we only know the likely type or region of asteroid, by matching how meteorites and asteroids reflect light, reconstructing fireball orbits and comparing with samples returned by spacecraft. Only a few meteorite groups have been linked to a specific named body.
Linking a stone in a museum to a body hundreds of millions of kilometres away is detective work, and the clues come from several directions. The first is reflected light. Telescopes can measure how much sunlight an asteroid reflects at different wavelengths, a pattern called its spectrum, which reveals minerals on its surface. Laboratories measure the same thing for meteorites. In 1970, astronomers found that the spectrum of asteroid Vesta matched basaltic meteorites, now called the HED group, and NASA's Dawn spacecraft strengthened that link when it orbited Vesta in 2011 and 2012.
The second is orbits. When a fireball is filmed by several cameras, scientists can calculate where the meteoroid came from before it entered the atmosphere. Dozens of recovered falls now have known orbits, most pointing back to the inner asteroid belt. The most dramatic case came in 2008, when the small asteroid 2008 TC3 was discovered hours before it struck Earth over Sudan. Its fragments, the Almahata Sitta meteorites, are the first to be collected from an asteroid observed in space beforehand.
The third is sample return. Japan's Hayabusa mission brought back dust from asteroid Itokawa in 2010, which matched LL ordinary chondrites. Hayabusa2 and NASA's OSIRIS-REx later returned material from Ryugu and Bennu, which resembles carbonaceous chondrites. These ground truth checks show how spectra relate to real rock.
Finally, researchers combine all of this with computer models of how fragments escape the asteroid belt and with exposure ages that show when a meteoroid broke free. Studies in 2024 used this approach to trace many ordinary chondrites to particular young asteroid families. Still, for most meteorites, the parent body remains unidentified.