While carbonaceous chondrites make up only a small portion of the meteorites sampled on Earth, CO chondrites make up a very tiny fraction of those meteorites. According to the study, these types of meteorites are among the most pristine materials in our Solar System.

According to the study, the Cretaceous-Paleogene impactor was about six to nine miles wide and created a massive crater in the Yucatán Peninsula in Mexico. It was eventually named the Chicxulub crater.

“Being impacted by such a rare, distant projectile really underscores how unlucky the dinosaurs were,” Claeys said.