Presolar Grain Searching

This is the type of data we look at to identify isotopically anomalous presolar grains (micrometer sized dust that formed around other stars before the Solar System’s formation).

The left image shows the ratio of oxygen-17 to oxygen-16 in a 10×10 micron region of a primitive meteorite. You can see one small grain on the left is enriched in oxygen-17 by ~2000 per mil, which means it has twice as much oxygen-17 as terrestrial matter. On the right is the plot on the left divided by the statistical uncertainty of each pixel. This shows that the oxygen-17 anomaly is indeed statistically significant, close to 20-sigma.