A longstanding mystery resolved
Using the James Webb Space Telescope and the Hubble Space Telescope, astronomers have determined the true nature of the stellar system Terzan 5. Previously classified as a conventional globular cluster, the new data show that it is a surviving fragment from the Milky Way’s formative epoch.
Observations and analysis
JWST provided high‑resolution infrared imaging that resolved the complex stellar populations within Terzan 5. Complementary optical measurements from Hubble enabled precise age dating. The combined datasets reveal at least two distinct generations of stars separated by several billion years— a characteristic absent in genuine globular clusters.
Implications for galaxy formation
The findings suggest that Terzan 5 represents a piece of a proto‑galactic structure that was later incorporated into the present‑day Milky Way. Such relics offer valuable insight into how large galaxies assemble from smaller building blocks and the star‑formation processes involved.
Future prospects
The study paves the way for examining other ambiguous clusters to assess their origins. Continued observations with JWST, Hubble and upcoming facilities will further refine our picture of the Milky Way’s early history.