Co-paired stars, or stars that travel together, can provide insights into processes that other stars can’t. Differences in their brightness, orbits, and chemical composition can hint at different features, and scientists are beginning to exploit them. A new paper from researchers in Australia, China, the US, and Europe analyzed data to determine if one of those features – specifically the depletion of particular elements in a star – could be a sign that it has formed a planet, or if it ate one.