The James Webb Space Telescope has peered inside one of the oldest star clusters of our Milky Way galaxy, revealing a region of our galactic halo teeming with brilliant stars.
The James Webb Space Telescope observed the Messier 92 globular cluster, also known as M92, early after coming online last summer. It took only one hour to capture the sparkling image above, according to a statement by the Space Telescope Science Institute, which operates the observatory and released the image on Feb. 22.
Primarily built to study the most distant objects in the far-away reaches of the universe, Webb easily detected the multitude of stars inhabiting the M92 cluster some 27,000 light-years away, including the dim and cool ones that were invisible to its predecessor, the Hubble Space Telescope. Some of the stars in this image are tiny, only 0.1 the mass of our sun, Roger Cohen, an astronomer at Rutgers University and one of the scientists behind the observations, said in the statement.
"This is very close to the boundary where stars stop being stars," Cohen said. "Below this boundary are brown dwarfs, which are so low-mass that they're not able to ignite hydrogen in their cores."
The image, captured by Webb's Near Infrared Camera (NIRCam), reveals only a small portion of the M92 cluster. The entire cluster is about 100 light-years wide and is teeming with 300,000 stars. If an inhabited planet like Earth were to orbit one of those stars, the creatures on its surface would have a magnificent view of the night sky, which would shine with thousands of stars that would be thousands of times brighter than those humans can see from Earth.
M92 is one of the oldest globular clusters in the Milky Way, consisting of stars that formed 12 to 13 billion years ago, when the universe was only hundreds of millions years old.
"It contains some of the oldest stars that we can find, or at least that we can resolve and characterize well," said astronomer Matteo Correnti of the Italian Space Agency, who helped analyze the data, in the statement.
By studying ancient clusters such as M92, astronomers can gain important insights into the history of not only our Milky Way galaxy, but the entire universe.
"Globular clusters like M92 are very important for our understanding of stellar evolution," astronomer Alessandro Savino of the University of California, another member of the Webb science team, said in the statement. "For decades they have been a primary benchmark for understanding how stars work, how stars evolve. M92 is a classic globular cluster. It's close by; we understand it relatively well; it's one of our references in studies of stellar evolution and stellar systems."
Most of the stars in the cluster have formed at about the same time and contain the same chemical elements. Some of these stars, however, are more massive than others, and Webb can help better describe the entire population.