We and our toothpaste are star stuff

The heavier chemical elements have their origins in ancient stars, now astronomers have demonstrated that fluorine is certainly among their number and came from long-dead cousins of our nearest and dearest star, the Sun. Nils Ryde of Lund University, Sweden, and colleagues in Ireland and the USA, studied stars formed at different times in the history of the universe to see if the amount of fluorine they contain agrees with theory using infrared spectroscopy. Fluorine is formed towards the end of the star’s life, when it has expanded to become what is known as a red giant. Tracking the elemental composition of stars allows astronomers to validate their theories of stellar evolution.