Skip to main content

How James Webb is peering into galaxies to see stars being born

Recently astronomers used the James Webb Space Telescope to look at the structures of dust and gas which create stars in nearby galaxies. Now, some of the researchers have shared more about the findings and what they mean for our understanding of how galaxies form and evolve.

The project, called Physics at High Angular resolution in Nearby Galaxies, or PHANGS, used James Webb to observe several galaxies which are similar to our own Milky Way to see how stars are forming within them.

A view of the inside of a distant spiral galaxy.
Researchers are getting their first glimpses inside distant spiral galaxies to see how stars formed and how they change over time, thanks to the James Webb Space Telescope’s ability to pierce the veil of dust and gas clouds. NASA/Space Telescope Science Institute

“We’re studying 19 of our closest analogues to our own galaxy,” explained one of the researchers, Erik Rosolowsky of the University of Alberta, in a statement. “In our own galaxy, we can’t make a lot of these discoveries because we’re stuck inside it.”

By using Webb’s infrared instruments, the researchers can look through clouds of dust and gas which could be opaque if viewed in the visible light range. As objects get warmer, they give off more infrared light, so Webb’s instruments can see where pockets of warmer dust and gas sit, and how this relates to areas where stars are forming.

“At 21 micrometers [the infrared wavelength used for the images collected], if you look at a galaxy you will see all of those dust grains heated with light from the stars,” said Hamid Hassani, another of the researchers. “The infrared light is really key to tracing the cold and distant universe.”

The team has so far examined 15 galaxies, out of a total of 19 that they will examine for their project. For the galaxies imaged so far, the researchers took information about the distribution and warmth of stars and worked out the ages of those stars. That came with some surprises, as many of the images they were observing showed bright stars that were younger than they were expecting.

“The age of these [stellar] populations is very young. They’re really just starting to produce new stars and they are really active in the formation of stars,” said  Hassani.

It is the process of star formation which makes a galaxy grow and thrive. Star formation is a delicate balance of having enough material for new stars to form, and the stellar winds created by young stars blow this material away.

“If you have a star forming, that galaxy is still active,” Hassani said. “You have a lot of dust and gas and all of these emissions from the galaxy that trigger the next generation of the next massive star forming and just keep the galaxy alive.”

The research is published in The Astrophysical Journal Letters.

Editors' Recommendations

Georgina Torbet
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
See the stunning first images taken by the dark matter-hunting Euclid telescope
The Horsehead Nebula, also known as Barnard 33, is part of the Orion constellation. About 1,375 light-years away, it is the closest giant star-forming region to Earth. With Euclid, which captured this image, scientists hope to find many dim and previously unseen Jupiter-mass planets in their celestial infancy, as well as baby stars.

The European Space Agency (ESA) has released the first full-color images taken by Euclid, a space telescope that was launched earlier this year to probe the mysteries of dark matter and dark energy. Euclid will image a huge area of the sky to build up a 3D map of the universe, helping researchers to track the dark matter that is clustered around galaxies and the dark energy that counteracts gravity to push galaxies apart.

The Horsehead Nebula, also known as Barnard 33, is part of the Orion constellation. About 1,375 light-years away, it is the closest giant star-forming region to Earth. With Euclid, which captured this image, scientists hope to find many dim and previously unseen Jupiter-mass planets in their celestial infancy, as well as baby stars. ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi; CC BY-SA 3.0 IGO

Read more
James Webb snaps an image of the famous and beautiful Crab Nebula
NASA’s James Webb Space Telescope has gazed at the Crab Nebula in the search for answers about the supernova remnant’s origins. Webb’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument) have revealed new details in infrared light.

Located 6,500 light-years away, the Crab Nebula is famous among astronomers for its elaborate and beautiful structure. A new image from the James Webb Space Telescope shows off the gorgeous nebula as seen in the infrared wavelength, highlighting the filaments of dust that create its cage-like shape.

The nebula is a supernova remnant, the result of a massive star that exploded at the end of its life centuries ago. The supernova was observed on Earth in 1054 CE, and since then astronomers have watched the nebula that resulted from that explosion grow and change.

Read more
James Webb observes merging stars creating heavy elements
This image from Webb’s NIRCam (Near-Infrared Camera) instrument highlights GRB 230307A’s kilonova and its former home galaxy among their local environment of other galaxies and foreground stars. The neutron stars were kicked out of their home galaxy and travelled the distance of about 120,000 light-years, approximately the diameter of the Milky Way galaxy, before finally merging several hundred million years later.

In its earliest stages, the universe was composed mostly of hydrogen and helium. All of the other, heavier elements that make up the universe around us today were created over time, and it is thought that they were created primarily within stars. Stars create heavy elements within them in the process of fusion, and when these stars reach the ends of their lives they may explode in supernovas, spreading these elements in the environment around them.

That's how heavier elements like those up to iron are created. But for the heaviest elements, the process is thought to be different. These are created not within stellar cores, but in extreme environments such as the merging of stars, when massive forces create exceedingly dense environments that forge new elements.

Read more