Posted by Researchers have proposed a new adaptive quantum-optimal imaging method that could help astronomers directly detect faint exoplanets located extremely close to their host stars. The study, conducted by researchers from Hanyang University, Sungkyunkwan University and Purdue University, focuses on one of the hardest problems in exoplanet astronomy: separating a tiny planetary signal from overwhelming starlight.
Terrestrial planets can be billions of times fainter than their stars. An Earth–Sun analogue has a planet-to-star contrast of roughly 10⁻¹⁰, while potentially habitable planets around nearby M dwarfs can reach approximately 10⁻⁷–10⁻⁸. Many also appear at angular separations near or below a telescope’s diffraction limit, where conventional coronagraphs struggle to distinguish the planet.
The proposed technique takes a different approach. Instead of relying only on suppressing starlight, it sorts incoming photons into specially selected spatial modes. The measurement basis is repeatedly updated to maximize the quantum Fisher information – the amount of useful information extracted from each detected photon. The algorithm simultaneously estimates the number, positions and brightnesses of sources and uses the Bayesian information criterion to determine how many sources are actually present without requiring a manually chosen detection threshold.
In simulations involving one bright star and two faint companions separated by less than half a Rayleigh unit, the system detected companions with contrasts down to 10⁻⁸. Across 12,000 trials, complete scenes were recovered with a mean success rate of 72.5%, while successfully recovered sources achieved subpixel positional accuracy. The technique also remained effective when the optical system was misaligned, achieving a 71.3% success rate, and performed near 80% across broad regions when source brightness ratios were randomized.
However, the results remain a proof of principle based entirely on simulations. Real telescopes introduce aberrations, background light, detector noise, crosstalk and other complications that must be incorporated before experimental deployment.
