One of these twin stars has likely been snacking on exoplanets

Astronomers have discovered chemical differences between binary stars that indicate one is a cosmic cannibal that has devoured at least one planet. Binary stars should have the same chemical composition because each star is formed from the same vast cloud of gas and dust; however earlier this year the team behind this new research discovered that the two stars of HD 81809, located around 101 light-years away, are chemically different. One of the stars, HD 81809B, has a much greater concentration of elements heavier than hydrogen and helium, which astronomers call "metals," at its surface than its binary partner HD 81809A. This new research suggests that the reason for the metal enrichment of HD 81809B is that this star has consumed an exoplanet which was between 50 and 75 times the size of Earth . "This is the first binary system to be found with this chemical difference, which is very unusual," team leader Nuno Moedas of the Technical University of Denmark told Space.com. "Binary systems are 'like siblings' in that they are born from the same molecular cloud, meaning they have the same chemical composition. As with siblings, some differences in element abundances can appear due to physical processes. However, these differences will be much smaller than those of HD 81809." Moedas added that there are only two possible explanations for the differences between HD 81809B and HD 81809A. …