In a new study, a team of astronomers report that they have captured the most detailed glimpse yet of a red supergiant before it exploded.
Using JWST’s powerful infrared vision, the researchers identified the star that produced a supernova, marking the first time that the powerful space telescope has detected a supernova progenitor.
“It’s the reddest, dustiest red supergiant that we’ve seen explode as a supernova,” study co-author Aswin Suresh, a graduate student in physics and astronomy at Northwestern, said in the same statement.
The best-known example of such a star is Betelgeuse, the bright red shoulder of Orion and the closest known red supergiant, which is speculated to explode within the next 10,000 to 100,000 years.
Astronomers have long puzzled over the apparent lack of luminous red supergiant stars in pre-explosion images, even though models predict that these stars should dominate the population of core-collapse supernova progenitors.
Astronomers have been looking for a population of doomed stars—massive red supergiants that, according to theory, should die in fierce stellar explosions but inexplicably seldom do—in the sky for decades. In fact, the mystery may finally be being solved thanks to the James Webb Space Telescope (JWST).
In a recent study, a group of astronomers claim to have seen a red supergiant in greater detail than they have seen before it exploded. For the first time, the powerful space telescope has detected a supernova progenitor when the researchers used JWST’s powerful infrared vision to identify the star that produced a supernova.
On Wednesday, October, the results were released. 8) in The Astrophysical Journal Letters, imply that while many of these massive stars do explode, they are merely prevented from being seen by most telescopes due to dense dust clouds.
“We’ve been waiting for this to happen — for a supernova to explode in a galaxy that JWST had already observed,” said study lead Charlie Kilpatrick of Northwestern University in a statement. It is only now, with JWST, that we have the quality of data and infrared observations necessary to identify the precise kind of red supergiant that burst and the characteristics of its immediate surroundings. “,”.
SN 2025pht, the supernova, was discovered on June 29 in a galaxy approximately 40 million light-years away from Earth. The Hubble Space Telescope and JWST had previously taken pictures of this area prior to the explosion; JWST had done so twice in 2024, and Hubble had done so as early as 1994. Kilpatrick’s team identified the particular star that exploded later by comparing these pre-explosion datasets, the study, which was published on the preprint archive arXiv in August, claims. 14. 14.
According to the study, the team meticulously aligned the Hubble and JWST images using 36 stars that were visible in both datasets as reference points to confirm the match, making sure that each pixel matched the same location in the sky.
The exact location of the supernova was then contrasted with all sources found in the earlier, pre-explosion photos. They verified that the object seen by both telescopes prior to the explosion was the progenitor star that became SN 2025pht by identifying a single bright, point-like source in those earlier observations that was visible across all JWST images precisely where the supernova later appeared in a post-explosion Hubble image.
These pictures showed a star that was extremely red and bright, so red that it was obvious that a thick layer of dust was covering it. The star’s visible light was reduced by more than 100 times, despite the fact that it shone roughly 100,000 times brighter than our sun, the statement said.
“It’s the reddest, dustiest red supergiant that we’ve seen explode as a supernova,” According to the same statement, Aswin Suresh, a Northwestern graduate student studying physics and astronomy, co-authored the study.
Because we lacked the high-quality infrared data that JWST can now offer, Kilpatrick continued, “that tells us that previous explosions might have been much more luminous than we thought.”.
Astronomers refer to stars like SN 2025pht as red supergiants, which are enormous stars nearing the end of their lives. Gravity forces them inward when their cores run out of fuel, resulting in supernovae that leave behind a black hole or neutron star.
Betelgeuse is the most well-known example of such a star. It is the nearest red supergiant and the bright red shoulder of Orion. It is predicted to explode in the next 10,000 to 100,000 years.
Although models predict that luminous red supergiant stars should dominate the population of core-collapse supernova progenitors, astronomers have long been perplexed by the apparent lack of these stars in pre-explosion images. According to the latest findings, many might just be obscured by dense dust layers, making them invisible to optical telescopes.
“Even I didn’t expect to see such an extreme example as SN2025pht,” Kilpatrick stated, despite his support for that interpretation.
The group also discovered that, in contrast to the silicate-based dust commonly observed in red supergiants, the dust surrounding the progenitor star was abnormally rich in carbon. This might suggest that during the star’s last years, strong convection deep within the star dredged up carbon from its core, altering its chemistry just before it burst apart, the study says.
In addition to resolving a long-standing mystery, scientists say the discovery provides new insight into the life cycles of massive stars. Astronomers will be able to follow more of these hidden giants as they die thanks to JWST and the upcoming Nancy Grace Roman Space Telescope.
“This is an exciting time to study massive stars and supernova progenitors,” Kilpatrick said in the statement, referring to the upcoming launch of Roman and the JWST. “We will produce data of a higher caliber and new discoveries than have been seen in the previous 30 years. “.”.
