Last month, Japan's Hayabusa2 mission brought home a cache of rocks collected from a near-Earth asteroid called Ryugu. While analysis of those returned samples is just getting underway, researchers are using data from the spacecraft's other instruments to reveal new details about the asteroid's past.

In a study published in Nature Astronomy, researchers offer an explanation for why Ryugu isn't quite as rich in water-bearing minerals as some other asteroids. The study suggests that the ancient parent body from which Ryugu was formed had likely dried out in some kind of heating event before Ryugu came into being, which left Ryugu itself drier than expected.