> This is really weird. No known isotope of promethium has a half-life longer than 17.7 years, meaning that it must be produced by some continuous process if we are to see it in Przybylski's star. Further analysis showed it contains actinium, protactinium, neptunium, plutonium, americium, curium, berkelium, californium, and einsteinium. These are difficult to confirm because they do not occur in nature (except, it seems, in Przybylski's star).

They're searching for natural explanations to rule out alien life. Very very cool. Quite a variety. Lots to learn from this star.