New Method Boosts Webb’s Planet-Hunting Sensitivity Up to 15 Times and Finds a Planet Hidden in Old Data

A new image-processing method has pulled a known giant planet out of James Webb Space Telescope data where standard techniques saw only starlight, and it boosted the telescope’s sensitivity to faint planets by 2 to 15 times. The JWST exoplanet imaging technique, called FLIP, is described in a study published Nov. 4 in Nature by a team led by Northwestern University.

The advance requires no new hardware. It works by modeling the telescope itself in fine detail, which means astronomers can go back through years of archived observations looking for planets they missed.

The glare problem in JWST exoplanet imaging

“Planets are a million times fainter than their stars,” said lead author Rodrigo Ferrer-Chavez, a Ph.D. student in astronomy at Northwestern, in the university’s announcement. “Slight shifts or tilts, even on the scale of just a few nanometers, can change the pattern of light.”

Telescopes like Webb use coronagraphs to block a star’s light, but some still leaks through as a hazy pattern. For about 20 years, astronomers have handled that by photographing a different star and subtracting its image as a reference, said co-author Jason Wang, an assistant professor of physics and astronomy at Northwestern. The catch is that no telescope stays perfectly still. Tiny thermal changes can make a mirror expand or contract by a picometer, and the motors in Webb’s cryocoolers can make mirrors vibrate, so the reference never quite matches.

How FLIP builds a digital twin of Webb

FLIP, short for Physics-based Learning for Imaging Planets, creates a “digital twin” of the telescope that simulates how starlight travels through its mirrors to the detectors. Using optimization tools like those used to train AI models, the team tuned millions of parameters until the model matched each real observation, then subtracted the simulated glare.

“We used the same computational tools that researchers use to train AI models, but we did not actually use AI,” Wang said. “Because we already know the physics, we don’t need AI to understand what’s happening.”

A planet hiding in two-year-old data

The team tested FLIP on archived Webb observations of three stars, shown below.

The standout result was 51 Eridani b, a giant planet first found with ground-based telescopes. Conventional processing could not separate it from leftover glare in Webb images taken at 4.3 microns, a wavelength where carbon dioxide in the planet’s atmosphere absorbs light and dims its signal. With FLIP, the planet emerged from the same two-year-old data.

“This is real data in a real scenario,” Wang said. “It was science left on the table because we didn’t have the right tools to analyze the data in the most optimal way.” Because 4.3 microns is where carbon dioxide absorbs strongly, detections there could offer new clues about a planet’s atmosphere and makeup.

Outside scientists were impressed. “This is really amazing to see,” astronomer Sasha Hinkley of the University of Exeter told Science. “It’s hard to argue with results,” added Bruce Macintosh, director of the University of California Observatories. Hinkley pointed to a practical payoff: no longer spending scarce telescope time on reference stars. “The implications of this are huge,” he said. “We could cut our observing time into a fraction of what it is now and observe many more stars and observe many more planets, and get better images, too.”

The team is now re-examining all of Webb’s coronagraphic images taken so far, which number in the hundreds, Science reported. Macintosh expects the technique to become routine for Webb observations.

Why it matters for finding another Earth

The longer-term payoff could come with NASA’s proposed Habitable Worlds Observatory, which aims to photograph Earth-like planets around sun-like stars. Northwestern said that telescope may need optical stability at the picometer scale, roughly 100 to 1,000 times more stable than Webb. FLIP suggests a different path: correct for a telescope’s tiny imperfections in software rather than engineering them all away.

“We know of no planets around other stars that are like those in our own solar system,” Ferrer-Chavez said. “It’s not that they don’t exist. It’s that we cannot see them.”

The study adds to a busy stretch for space telescopes. Hubble recently showed that 37 dwarf galaxies kept only about 11% of the oxygen their stars made, and Hubble and Webb together captured the Cat’s Head Nebula in the Carina Nebula. The research was supported by the Space Telescope Science Institute, the Sloan Foundation and the National Science Foundation.

Sources

• Ferrer-Chavez et al., “Imaging exoplanets below the telescope stability limit,” Nature (Nov. 4, 2026)
• Northwestern University: Hidden planet emerges from the glare
• Science: Astronomers sharpen JWST’s view of distant worlds