Look! New Webb Telescope Image Shows 300,000 Stars in Incredible Detail
M92 is a globular cluster full of stars.
Behold Messier 92, a dense place in the nearby Universe where more than 300,000 stars live with their siblings.
Messier 92 is located within the Milky Way galaxy about 27,000 light-years away in the Hercules constellation. Astronomers define stellar hubs like Messier 92 as globular clusters, home to hundreds of thousands of huddled stars born roughly at the same time. In the case of this glittering scene, the stars emerged from the same clump of material about 12 and 13 billion years ago. This makes it one, if not the oldest, known globular cluster in the Milky Way. That’s quite the standard for a galaxy that contains roughly 100 billion stars.
Like homemade cookies packed onto a baking sheet and put in an oven at the same time, these stars are similar ages but are different sizes. Astronomers are particularly interested in how the James Webb Space Telescope (JWST) can advance what’s gleaned about the smallest of this stellar batch. Those less massive than the Sun are important to understand for a few reasons.
Cool low-mass stars are the most numerous in the Universe, according to a Q&A that NASA published alongside the new JWST image on Wednesday.
“[F]rom a theoretical point of view, they are very interesting because they've always been very difficult to observe and characterize. Especially stars less than half the mass of the Sun, where our current understanding of stellar models is a little more uncertain,” Alessandro Savino, a postdoc at the University of California, Berkeley, said.
JWST imagery of these low-mass objects may also reveal information about the evolution of stars.
“Studying the light these low-mass stars emit can also help us better constrain the age of the globular cluster. That helps us better understand when different parts of the Milky Way (like the halo, where M92 is located) formed. And that has implications for our understanding of cosmic history,” Matteo Correnti, a research fellow at the Space Science Data Center at the Italian Space Agency and National Institute of Astrophysics in Rome, Italy, shared in the Q&A.
The Near-Infrared Camera (NIRCam) obtained the image of Messier 92 in June 20, 2022, as part of the Early Release Science program. The image is a composite of four exposures.
If the new image looks like you’re viewing the cluster through one massive window, there’s a reason.
“The black strip in the center is a chip gap, the result of the separation between NIRCam’s two long-wavelength detectors. The gap covers the dense center of the cluster, which is too bright to capture at the same time as the fainter, less dense outskirts of the cluster,” NASA says.