Isotopes are versions of elements with the same number of protons, but a different number of neutrons. (sciencedaily.com)
Another is to analyze the traces of isotopes — versions of elements with the same number of protons, but a different number of neutrons — found in primitive meteorites. (sciencedaily.com)
For this study, the team set out to investigate the timing of supernova dust formation by measuring isotopes — versions of elements with the same number of protons but different numbers of neutrons — in rare presolar silicon carbide grains with compositions indicating that they formed in type II supernovae. (sciencedaily.com)