Populations of Stars (IMAGE) The Kavli Foundation Caption Observational data reveals the characteristics of variously aged stars observed in the globular cluster NGC 1783. Black points indicate stars 1.4 billion years and older, while green squares show the 890 million year old stars, and the purple squares along with the black points represented in the orange square to the right signify 450 million year old stars. The globular cluster clearly has three substantial populations of stars with different ages. A new study by astronomers from the Kavli Institute for Astronomy and Astrophysics at Peking University (KIAA), the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC), Northwestern University, and the Adler Planetarium suggests the globular cluster swept up stray gas and dust from outside the cluster to give birth to these successive generations of stars. Credit Credit: Chengyuan Li and Richard de Grijs, KIAA Usage Restrictions This image be used when accompanied by the appropriate caption and credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.