NASA’s Webb Telescope Identifies the Star That Became Supernova 2025pht

Around 40 million years ago, a massive star in a nearby galaxy met a dramatic end, exploding as a supernova and blasting stellar material into space. The intense flash of light from that explosion traveled millions of light-years and finally reached Earth on June 29, 2025, where it was detected by the All-Sky Automated Survey for Supernovae (ASAS-SN).

The newly discovered explosion was officially named Supernova 2025pht. While many astronomers quickly began studying the bright event itself, another research team took a different approach.

Instead of focusing solely on the explosion, they searched archival images to identify the exact star that had existed before it detonated.

Their investigation paid off.

Using previous observations of the galaxy James Webb Space Telescope, scientists pinpointed a single red supergiant star in the exact location where the supernova now shines.

This marks the first published identification of a supernova progenitor using Webb data. The findings were released in Astrophysical Journal Letters.

Lead researcher Charlie Kilpatrick of Northwestern University described the discovery as a long-awaited milestone. By combining archived data from Hubble Space Telescope and Webb, the team was able to fully characterize the star before it exploded.

Pinpointing the Progenitor in Galaxy NGC 1637

The supernova occurred in the spiral galaxy NGC 1637, located millions of light-years away. By carefully aligning archival images taken in 2024 with Webb’s advanced instruments—MIRI (Mid-Infrared Instrument) and NIRCam (Near-Infrared Camera)—researchers identified the original star.

What they found was surprising.

The progenitor appeared extremely red, far redder than typical red supergiants observed before explosion.

This coloration strongly indicated the presence of thick surrounding dust, which absorbed shorter blue wavelengths and allowed only redder light to pass through.

Graduate student Aswin Suresh described it as the dustiest and reddest red supergiant ever observed exploding as a supernova.

Solving the Mystery of the “Missing Red Supergiants”

Astronomers have long faced a puzzling problem: theory predicts that the most massive stars should be the brightest and easiest to detect before they explode. Yet, in many cases, these expected progenitors appear to be missing from archival images.

This discrepancy has been referred to as the “missing red supergiants” problem.

One possible explanation is that the most massive aging stars produce enormous amounts of dust in their final stages. That dust could obscure their brightness so dramatically that telescopes struggle to detect them.

The observations of Supernova 2025pht strongly support this idea.

Even Kilpatrick, who had previously advocated for the dust-obscuration explanation, admitted the amount of dust in this case exceeded expectations. If massive red supergiants routinely surround themselves with thick dust shells, it would explain why many appear absent in earlier observations.

Unexpected Carbon-Rich Dust

Another intriguing discovery involved the composition of the dust itself.

Using computational models to analyze Webb’s infrared data, scientists determined that the dust surrounding the star was likely carbon-rich, rather than the silicate-rich material typically expected around such stars.

This suggests that shortly before its explosion, the star may have dredged carbon up from its interior and expelled it into space in episodic outbursts — almost like stellar “burps.”

Mid-infrared observations from Webb’s instruments were critical in determining the dust’s composition. Without these wavelengths, identifying the material would have been far more difficult.

Looking Ahead: The Role of the Nancy Grace Roman Space Telescope

Researchers are now searching for other dust-enshrouded red supergiants that may explode in the near future.

Future observations from the upcoming Nancy Grace Roman Space Telescope could dramatically improve these efforts. With high resolution, advanced sensitivity, and broad infrared capabilities, Roman may detect similar stars and even observe their late-life variability as they expel large quantities of dust before exploding.

Such discoveries could help astronomers predict supernova events before they occur — a major breakthrough in stellar evolution research.

Why This Discovery Matters?

The James Webb Space Telescope continues to redefine modern astronomy. As NASA’s leading space observatory, developed in partnership with European Space Agency and Canadian Space Agency, Webb is helping scientists:

• Investigate stellar life cycles
• Understand dust formation in massive stars
• Explore distant galaxies
• Probe the origins of the universe

By successfully identifying the progenitor of Supernova 2025pht, Webb has provided crucial evidence supporting the theory that massive red supergiants may hide behind thick carbon-rich dust shells before exploding.

The identification of the progenitor star behind Supernova 2025pht represents a historic milestone in astronomy. By combining archival data from Hubble and infrared observations from Webb, scientists confirmed that the exploding star was an exceptionally dusty, carbon-rich red supergiant.

This discovery strengthens the theory that the long-standing mystery of the “missing red supergiants” can be explained by extreme dust obscuration. It also opens the door for future discoveries using advanced observatories like the Nancy Grace Roman Space Telescope.

As infrared astronomy continues to evolve, we are entering an era where astronomers may not only study supernovae after they explode—but potentially anticipate them before they happen.

FAQs