Actinium

Actinium is a rare and highly radioactive element that is sparsely distributed in the universe. As a member of the actinide series, it shares similarities with other heavy elements and exhibits high radioactivity and instability. In astronomical contexts, actinium's presence is notably scarce, with minimal occurrences in celestial bodies such as stars, planets, or cosmic entities. Its isotopes, particularly actinium-227, have a relatively long half-life of about 21.8 years, yet its occurrence beyond terrestrial confines remains elusive. On Earth, trace amounts of actinium are sometimes found in uranium and thorium ores due to their decay processes, but its astronomical significance or impact on celestial observations remains largely negligible due to its rarity and limited presence in the universe beyond our planet.