Like Sherlock Holmes’s magnifying glass, the NASA/ESA Hubble Space Telescope can peer into an astronomical mystery in search of clues. The enigma in question concerns the globular cluster Ruprecht 106, pictured here. Unlike most globular clusters, Ruprecht 106 may be what astronomers call a single population globular cluster. While the majority of stars in a globular cluster formed at approximately the same location and time, it turns out that almost all globular clusters contain at least two groups of stars with distinct chemical compositions. The newer stars will have a different chemical make-up that includes elements processed by their older, massive cluster companions. A tiny handful of globular clusters do not possess these multiple populations of stars, and Ruprecht 106 is a member of this enigmatic group.
Hubble captured this star-studded image using one of its most versatile instruments, the Advanced Camera for Surveys (ACS). Much like the stars in globular clusters, Hubble’s instruments also have distinct generations: ACS is a third-generation instrument which replaced the original Faint Object Camera in 2002. Some of Hubble’s other instruments have also gone through three iterations: The Wide Field Camera 3 replaced the Wide Field and Planetary Camera 2 (WFPC2) during the last servicing mission to Hubble. WFPC2 itself replaced the original Wide Field and Planetary Camera, which was installed on Hubble prior to its launch.
Astronauts on the space shuttle serviced Hubble in orbit a total of five times and were able to either upgrade aging equipment or replace instruments with newer, more capable versions. This high-tech tinkering in low Earth orbit has helped keep Hubble at the cutting edge of astronomy for more than three decades.
Text credit: European Space Agency (ESA)
Image credit: ESA/Hubble & NASA, A. Dotter