A New Look at a Silent Progenitor
The James Webb Space Telescope (JWST) has offered astronomers a rare glimpse of a hidden star on the eve of its dramatic finale. In a study published in The Astrophysical Journal Letters, researchers report that the progenitor of the supernova SN 2025pht—an enormous red supergiant—was virtually invisible in visible light but revealed in infrared wavelengths captured by JWST. This finding provides a crucial clue to why some of the largest stars end their lives in dazzling explosions while remaining shrouded by dust clouds.
SN 2025pht: A Nearby, Yet Enigmatic, Explosion
SN 2025pht exploded in the galaxy NGC 1637, roughly 38 million light-years from Earth. The event was first flagged by the All-Sky Automated Survey for Supernovae and subsequently examined in detail by combining historical data from the Hubble Space Telescope with fresh JWST imaging. By comparing images taken before and after the blast, the team could pinpoint the light source that eventually vanished in the supernova and identify its structure just prior to detonation.
The Dusty Truth About Red Supergiants
Red supergiants are among the largest stars known, often hundreds to thousands of times bigger than the Sun. Theoretical models have long predicted that the most massive aging stars should explode as supernovae, yet these events are surprisingly underreported in astronomical surveys. The new JWST observations support a leading hypothesis: many red supergiants end their lives veiled by thick dust, which absorbs visible light and re-emits it at infrared wavelengths. In the case of SN 2025pht, the progenitor shone about 100,000 times brighter than the Sun, but its dust cloak made the star appear more than 100 times dimmer in visibility bands that humans can see.
JWST’s Infrared Advantage
JWST’s sensitivity to infrared light is crucial for these discoveries. Shorter wavelengths are readily blocked by dust, but infrared can penetrate the cocoon surrounding a dying star. As a result, JWST has opened a window into the final stages of stellar evolution that was previously inaccessible with optical telescopes. The implications extend beyond one supernova: the work helps quantify how much of the light from these explosions is hidden in the dust-laden environments in which massive stars live and die.
Implications for Future Supernova Studies
Lead author Charlie Kilpatrick of Northwestern University notes that this observation marks a turning point in identifying which red supergiants actually explode and what their surrounding environments look like just before detonation. The improved infrared data from JWST makes it possible to classify the exact type of red supergiant progenitors and to understand how dust affects the observed brightness of supernovae. As astronomers compile more pre-explosion images across different galaxies, we may finally close gaps in the long-standing mystery of red supergiant deaths.
Looking Ahead
While SN 2025pht provides a compelling case study, scientists stress that a larger sample is needed to generalize the dusty-progenitor model. JWST will be pivotal in this effort, offering high-resolution infrared data that can reveal concealed stars and their dusty shrouds in diverse galactic environments. In time, researchers hope to assemble a clearer, more complete picture of how the Universe’s most massive stars end their lives and how these cataclysmic events enrich their surroundings with heavy elements.
