Hubble and Webb probe the small objects beyond Neptune.

NASA reported on September 8 that a joint Hubble and Webb survey had examined 27 newly discovered small trans-Neptunian objects. The researchers found fewer small bodies than expected, while their colours followed relationships observed among larger distant objects.

Two papers in The Astronomical Journal describe the work. Combining visible-light and infrared observations lets researchers investigate populations that are difficult to characterize with either telescope alone. The results offer evidence about formation and later evolution, not a complete reconstruction of the Solar System’s history.