Newborn stars sculpt their galaxies in new James Webb telescope images

JWST’s sharp infrared eyes reveal stunning new details invisible to previous observatories

An image from the James Webb Space Telecope showing face-on spiral galaxy, NGC 628, with its whorls of colored gas and dust, pockmarked with dark areas.

New JWST images of face-on spiral galaxies like NGC 628 (shown) reveal whorls of gas and dust, pockmarked with dark voids. These voids are thought to be bubbles in the gas and dust created by radiation from young, massive stars, and by supernovas.

NASA, ESA, CSA, Judy Schmidt (CC BY 2.0)

A gaggle of galaxies crackle with intricate detail in new images from the James Webb Space Telescope. JWST’s sharp infrared eyes are revealing how newborn stars shape their surroundings, giving hints to how stars and galaxies grow up together.

“We were just blown away,” says Janice Lee, an astronomer at the University of Arizona in Tucson. She and more than 100 astronomers reported on scientists’ first look at these galaxies with JWST in a special February issue of the Astrophysical Journal Letters.

Before JWST launched in December 2021, Lee and her colleagues selected 19 galaxies that, if observed with the telescope, they thought could reveal new details of the life cycles of stars (SN: 1/24/22). These galaxies are relatively close, within 65 million light-years of the Milky Way, and all have different types of spiral structures. The team had observed the galaxies with many observatories, but parts of the galaxies had always looked flat and featureless.

“With [JWST], we’re seeing structure down to the very smallest scales,” Lee says. “For the first time, we’re seeing the youngest sites of star formation in a lot of these galaxies.”

A James Webb Space Telescope image of galaxy NGC 1365.
Astronomers are using JWST to study several galaxies with different types of spiral structures to compare how their stars form. NGC 1365 (shown) has a bright bar in its core that connects its spiral arms. JWST detected glowing dust in this galaxy’s center that had been obscured in previous observations.Science: NASA, ESA, CSA, Janice Lee/NOIRLab; Image processing: Alyssa Pagan/STScI

In the new images, the galaxies’ faces are pockmarked by dark voids amid glowing filaments of gas and dust. Comparisons to Hubble Space Telescope images reveal that these voids are bubbles carved out of the gas and dust by high-energy radiation from newborn stars in their centers.

Then, when the most massive of those stars reach the end of their life and explode, that gas gets pushed out even more. Some of the larger bubbles have smaller bubbles on their edges, which could indicate spots where the gas pushed by dying stars has started to build new stars.

Comparing these processes in different types of spiral galaxies will help astronomers understand how the galaxies’ shapes and properties influence the life cycles of their stars, and how the galaxies grow and change with their stellar denizens.

“We’ve only studied the first few [of the 19 selected] galaxies,” Lee says. “We need to study these things in the full sample to understand how the environment changes … how stars are born.”

Lisa Grossman is the astronomy writer. She has a degree in astronomy from Cornell University and a graduate certificate in science writing from University of California, Santa Cruz. She lives near Boston.

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