Humans have been gazing up at the stars twinkling in the dark night sky for thousands of years. But despite the long history of pondering these bright celestial bodies, there’s still a lot astronomers don’t know about how and why stars form.
A big reason why the star formation process has long remained shrouded in mystery is the lack of clear photos of regions of the universe where stars are born. But with its high-tech cameras and other sophisticated instruments, the James Webb Space Telescope is adding new chapters to the “stellar creation story,” according to a release from NASA.
The telescope’s latest achievement is a detailed mosaic image of the Tarantula Nebula, also known as 30 Doradus, a dazzling star-forming region some 161,000 light-years away from Earth in the Large Magellanic Cloud galaxy. Home to the most massive, hottest known stars in the universe, the Tarantula Nebula is one of the most intriguing “stellar nurseries” around, per NASA.
The nebula gets its creepy-crawly name from past telescope images, which showed dusty filaments that looked like hairy spider legs. In the new, crisper Webb image, which spans 340 light-years across, the nebula looks decidedly less spider-like—but astronomers are still thrilled with the photo. That’s because Webb captured thousands of previously unseen young stars that, when viewed through other telescopes, were always obscured by cosmic dust. The Webb photo also shows far-off background galaxies and offers a detailed look at the distribution of the nebula’s dust and gas.
Astronomers have long been interested in the Tarantula Nebula because it mimics what was happening during the so-called “cosmic noon,” a period of rapid star formation in the early universe.
Today, the Tarantula has a chemical composition that’s similar to the large star-forming regions of that period. And, because it’s relatively close to Earth compared to other nebulae, astronomers can study the Tarantula to get a better idea of what was happening during “the universe’s most active time,” writes New Scientist’s Leah Crane.
By contrast, the star-forming areas of the Milky Way do not have similar chemical compositions as nebulae during the cosmic noon and are not producing stars at the same quick pace as the Tarantula Nebula.
“Webb will provide astronomers the opportunity to compare and contrast observations of star formation in the Tarantula Nebula with the telescope’s deep observations of distant galaxies from the actual era of cosmic noon,” per NASA.
To get these new captures of the Tarantula Nebula, astronomers pointed three of the telescope’s high-resolution infrared cameras toward it. The Near-Infrared Camera (NIRCam) shows the Tarantula’s hollow center cavity, created by the “blistering radiation” and stellar winds emanating from massive, young, pale-blue stars, per NASA.
Moving out from the nebula’s center, the camera captured pillars brimming with very young protostars. The telescope’s Near-Infrared Spectrograph (NIRSpec) actually captured a protostar in the process of becoming a full-fledged star. Astronomers had suspected that the star was older, but Webb showed that it was much younger than they’d previously thought.
Without Webb’s instruments, “this episode of star formation-in-action could not have been revealed,” per NASA.
Meanwhile, Webb’s Mid-infrared Instrument (MIRI) turned its attention toward the nebula and captured its longer infrared wavelengths of light. This second view of the Tarantula shows its glowing gas and dust clouds, illuminated by the blue and purple hues of abundant hydrocarbons.
The Webb telescope launched in December 2021 and is already helping astronomers understand the universe more deeply. As it sends back stunning images of galaxies, new views of Jupiter and troves of other important data, Webb is picking up where its predecessor, the 32-year-old Hubble Space Telescope, falls short. The new high-tech, collaboratively built telescope represents “the whole force of human creativity,” as Webb's program scientist, Eric Smith, told Smithsonian magazine’s Shi En Kim last year.