An international team led by Zhao Gang of the National Astronomical Observatory of the Chinese Academy of Sciences was the first to find chemical evidence for the existence of "unstable supernovae" The research confirmed that the particular supernova originated from a first-generation star with a mass of up to 8 times the mass of the sun. Theorists, including some of the paper's authors, predicted that stars with masses higher than 150 times the sun might leave such unique imprints, but these imprints had never been definitively discovered before the paper.