Our sharpest view of the galaxy NGC 1637 is shown above. The supernova is actually visible within the frame but appears similar to the other stars (Image Credit: NASA, ESA, CSA, STScI, C. Kilpatrick (Northwestern), A. Suresh (Northwestern); Image Processing: J. DePasquale (STScI)).
For decades, scientists have been working with a fundamental problem: supernovas are almost always only discovered after they already explode. Because of this, it’s incredibly difficult to know what kind of star it was before it reached its final stages. But now, thanks to the James Webb Space Telescope, astronomers have made a major breakthrough by capturing a star both before and after its death. This is the first time a supernova’s original star has been identified in multiple wavelengths of light, giving us crucial information for knowing what it looked like before it exploded.
Hubble’s stunning capture of the spiral galaxy in which the new supernova resides (Image Credit: ESA/Hubble & NASA, D. Thilker).
The supernova shown below is titled SN 2025pht. It was originally discovered in June of 2025, in a galaxy 40 million light-years away named NGC 1637. Thankfully, both Hubble and Webb had previously photographed this galaxy, which allowed astronomers to compare the before-and-after views and data. By aligning these images over, each other, they were able to see a bright star right where they expected the supernova to be. They realized this was a luminous red supergiant, around 100,000 times the brightness of our Sun.
The full resolution image is shown above, with a box around the now famous supernova SN 2025pht, shining with a luminosity 100,000 times that of our Sun.
However, dust obscures much of the brightness of this explosion, which actually helps scientists in working on a long-standing mystery. In theory, red supergiants should account for a large amount of “core-collapse” supernovae, yet astronomers have found surprisingly few of them. But with JWST’s infrared capabilities, scientists noticed that the progenitor star appears extremely red and faint, with researchers describing it as the “reddest, dustiest red supergiant”, helping provide evidence that the missing massive stars may just be concealed behind dust.
This discovery confirms more than just the strange ways in which red supergiants explode. It also suggests to us that past supernovae may have been far brighter than what we thought. This is an extremely exciting era of supernova research, and future missions like NASA’s Nancy Grace Roman Space Telescope will continue uncovering the long-standing mysteries of stellar death.