FLIP: JWST NIRCam starlight subtraction finds 51 Eridani b

A team of astrophysicists led by Northwestern University has presented FLIP, a physics-based method of starlight subtraction, and applied it to observations from the Near-InfraRed Camera (NIRCam) coronagraph of the James Webb Space Telescope (JWST). According to the authors, sensitivity is 2–15 times higher than with standard techniques, including the first detection of the giant exoplanet 51 Eridani b at 4.3 μm dx.doi.org. The paper, cited via dx.doi.org, was published in Nature on 4 November 2026. The study was led by Rodrigo Ferrer-Chavez, a Ph.D. student in astronomy.

Starlight and telescope instabilities

Direct imaging requires suppressing the glare of the star, its point spread function (PSF). Even the brightest young giant planets are about 10^5 times fainter than their host stars in the near-infrared dx.doi.org. Standard algorithms build the PSF model from a library of reference images taken at other times or wavelengths, or of other stars dx.doi.org.

Such approaches are limited by instabilities. In space telescopes these are mostly pointing errors and thermal drifts, which make the reference and science PSFs differ and reduce sensitivity dx.doi.org. For the future Habitable Worlds Observatory, whose goal is to image Earth analogues around Sun-like stars (10^10 contrast), the stability requirement is at the picometre level, 100 to 1,000 times more stable than JWST dx.doi.org.

How FLIP works and what it found

FLIP first calibrates an instrument model on reference images so that it reproduces the reference PSF. It then solves for small changes in the telescope aberrations that better explain the science image dx.doi.org. The method combines multistep optimization with a flexible physical model and uses automatic differentiation to optimize millions of model parameters dx.doi.org. Earlier attempts at PSF subtraction with synthetic PSFs never produced sensitivity superior to standard techniques dx.doi.org.

The test case was an NIRCam observation of the star 51 Eridani in the F430M filter. The standard KLIP method did not detect the planet 51 Eridani b in the original analysis (Balmer et al. 2025). With FLIP the planet was detected at more than 5 sigma, at its expected location and with the expected morphology of the signal.

The authors state that the framework can be extended to other ground-based and space-based observatories, including the Nancy Grace Roman Space Telescope and the Habitable Worlds Observatory dx.doi.org.

FLIP method on JWST NIRCam data detects 51 Eridani b at 4.3 μm, with 2–15 times better sensitivity

Starlight and telescope instabilities

How FLIP works and what it found

Sources · 2

Read also

ACS emergency surgery verification linked to 28.8% lower 30-day mortality in a 55-hospital cohort