Credit: ESA/Hubble & NASA
Globular clusters
offer some of the most spectacular sights in the night sky. These
ornate spheres contain hundreds of thousands of stars, and reside in the
outskirts of galaxies. The Milky Way contains over 150 such clusters —
and the one shown in this NASA/ESA Hubble Space Telescope image, named NGC 362, is one of the more unusual ones.
As
stars make their way through life they fuse elements together in their
cores, creating heavier and heavier elements — known in astronomy as metals
— in the process. When these stars die, they flood their surroundings
with the material they have formed during their lifetimes, enriching the
interstellar medium with metals. Stars that form later therefore contain higher proportions of metals than their older relatives.
By
studying the different elements present within individual stars in NGC
362, astronomers discovered that the cluster boasts a surprisingly high
metal content, indicating that it is younger than expected. Although
most globular clusters are much older than the majority of stars in
their host galaxy, NGC 362 bucks the trend, with an age lying between 10
and 11 billion years old. For reference, the age of the Milky Way is
estimated to be above 13 billion years.
This image, in which you can view NGC 362’s individual stars, was taken by Hubble’s Advanced Camera for Surveys (ACS).
Source: ESA/Hubble/Images
