W.M. Keck Observatory | 2016 Sep 07
[img3="The Unusual Cluster Terzan 5 - Credit: NASA/ESA/Hubble/F. Ferraro"]https://cdn.spacetelescope.org/archives ... c1617a.jpg[/img3][hr][/hr]A fossilized remnant of the early Milky Way harboring stars of hugely different ages has been discovered by an international team of astronomers. This stellar system located in the Galactic Bulge has the appearance of a globular cluster, but it is like no other cluster known. It contains stars remarkably similar to the most ancient stars in the Milky Way but also a significant population of young stars, thus bridging the gap in understanding between our galaxy's past and its present. The research presents a possible route for astronomers to unravel the mysteries of galaxy formation, and offers an unrivaled view into the complicated history of the Milky Way. The findings are being published in The Astrophysical Journal today.
The system, called Terzan 5, has been classified as a globular cluster since its discovery 40 years ago. Now, an Italian-led team of astronomers has discovered that Terzan 5, which is 19 000 light-years from Earth, is like no other globular cluster known.
To make the discovery, the team scoured data from the Advanced Camera for Surveys and Wide Field Camera 3 on board Hubble; the second generation Near Infrared Camera (NIRC2) on the W. M. Keck Observatory located on Maunakea, Hawaii; and the Multi-conjugate Adaptive Optics Demonstrator (MAD) at ESO’s Very Large Telescope in Chile. The team found compelling evidence there are two distinct kinds of stars in Terzan 5, which not only vary in the elements they contain, but have an age-gap of roughly 7 billion years. ...
Astronomers Discover Rare Fossil Relic of Early Milky Way
ESO Science Release | 2016 Sep 07
Hubble Discovers Rare Fossil Relic of Early Milky Way
ESA Hubble Science Release | 2016 Sep 07
The Age of the Young Bulge-like Population in the Stellar System Terzan 5:
Linking the Galactic Bulge to the High-z Universe - F. R. Ferraro et al