Meteorite Puzzles: Unraveling Early Solar System Irradiation

Scientists delved into tiny particles called Spinel-HIBonite spherules (SHIBs) found in the Murchison meteorite. They focused on the isotopes of lithium (Li) and boron (B) to piece together the story of how these particles were irradiated in the early Solar System. The challenge was that these particles had extremely low beryllium (Be) levels, making it tough to track the extinct 10Be that would've been produced by irradiation. Instead, they looked at the original Li and B isotopic ratios, which are great at indicating when and how something was irradiated.They discovered that some of these SHIBs had unusual isotopic ratios—lower than expected for lithium and higher for boron. This led them to consider two scenarios from the early Solar System. The most likely one? Hibonite solids got irradiated first and then normal, isotopically balanced Li and B were added later.