Here on Earth, we can’t pick up any random rock and use it to understand the kinds of stars that went into our system’s formation; their contents are just too mixed by all the different factors that structured our world. We can, however, pick up some very particular rocks – meteorites – and study their contents to get unprocessed pockets of that original material. If you’ve ever bitten into a homemade cookie and found a blob of unmixed flour, you’ve hit the kind of unprocessed leftovers that researchers are looking for. 

In general, meteorites consist of outer layers of material that have been affected through interaction with sunlight and impacts with cosmic rays and other grains and rocks. In a lab, however, raw materials can be found. According to study lead author Nan Liu: Presolar grains have been embedded in meteorites for 4.6 billion years and are sometimes coated with solar materials on the surface. 

They used sensitive instruments that allowed them to knock grains off the meteorite very carefully, just molecules at a time. As they burrowed, they found that its chemistry changed both as a reflection of the contents of the meteorite but also in response to the ions used to burrow through the meteorite. By documenting both actual changes and ion gun related changes, they were able to explain odd abundances in other meteorites and to link the contents to different kinds of carbon stars. As Liu states: As we learn more about the sources for dust, we can gain additional knowledge about the history of the universe and how various stellar objects within it evolve.

More Information

WUSL press release

“New Multielement Isotopic Compositions of Presolar SiC Grains: Implications for Their Stellar Origins,” Nan Liu et al., 2021 October 12, The Astrophysical Journal Letters