Figure 18-13: Mass Loss from a Supermassive Star The Quintuplet Cluster is 25,000 ly from Earth. Inset: Within the cluster is one of the brightest known stars, called the Pistol. Astronomers calculate that the Pistol formed nearly 3 million years ago and originally had 100–200 M_⊙. The structure of the gas cloud suggests the star ejected the gas we see in two episodes, 6000 and 4000 years ago. The gas from any previous ejections is so thinly spread now that we cannot see it. The nebula shown in the inset is more than 1.25 pc (4 ly) across—it would stretch from the Sun nearly to the closest star, Proxima Centauri.

(2 MASS/UMass/IPAC-Caltech/NASA/NSF; inset: D. Filger, NASA)