NASA Telescopes Uncover Complex History of Milky Way's Terzan 5
Observations from NASA's James Webb and Hubble Space Telescopes have revealed that Terzan 5, an object orbiting within the Milky Way's central bulge, is not a typical globular star cluster. Researchers have definitively shown it to be a self-contained, self-enriching stellar system comprising up to four distinct star populations. This discovery offers new insights into how galaxies, including our own, form and evolve over cosmic time.
New observations from the James Webb Space Telescope, combined with archival data from the Hubble Space Telescope, confirm that Terzan 5 is a complex stellar system. It contains up to four different populations of stars and orbits within the crowded central bulge of the Milky Way galaxy.
Previously classified as a globular star cluster, which typically hosts only one ancient star population, Terzan 5 has been redefined. The new data not only verifies the presence of two distinct star populations but also provides evidence for two additional, more recent periods of star formation within the system.
Terzan 5, discovered by astronomer Azop Terzan in 1968, was found to harbor two distinct star populations in 2009. In 2016, Hubble observations estimated the ages of these populations, with one forming approximately 12 billion years ago, during the Milky Way's assembly, and another about 5 billion years ago. Webb's near-infrared capabilities allowed researchers to penetrate obscuring dust and catalog a greater number of fainter stars than previously possible.
Despite its location within the densely packed galactic bulge, Terzan 5 was massive enough to maintain its separate identity over billions of years. This allows it to serve as a "fossil fragment" providing clues about the early formation of our galaxy. The research was led by Giorgia Zullo, a PhD student at the University of Bologna.
These findings were presented at a press conference during the 248th meeting of the American Astronomical Society in Pasadena and have been published in the journal Astronomy & Astrophysics. (Source: NASA Breaking News)
