The James Webb Space Telescope (JWST) has directly imaged a previously unknown exoplanet, marking a significant milestone since the telescope's launch in 2022. Led by a CNRS researcher at the Observatoire de Paris-PSL and Universite Grenoble Alpes, the discovery was enabled by a coronagraph developed in France and installed on JWST's MIRI instrument.
This technology, created through a CNRS by Erica Marchand
Paris, France (SPX) Apr 10, 2025
The James Webb Space Telescope (JWST) has directly imaged a previously unknown exoplanet, marking a significant milestone since the telescope's launch in 2022. Led by a CNRS researcher at the Observatoire de Paris-PSL and Universite Grenoble Alpes, the discovery was enabled by a coronagraph developed in France and installed on JWST's MIRI instrument.
This technology, created through a CNRS-CEA collaboration, functions by masking a star's light to reveal nearby, dimmer objects-similar to what occurs during a solar eclipse. Using this method, researchers detected the planet embedded within a disk of rocky debris. It is the first exoplanet to be discovered directly by JWST.
Targeting youthful star systems observable from a top-down perspective, scientists focused on those that are only a few million years old. These systems often contain hot, young planets that shine brightly in mid-infrared light, a spectrum where JWST excels. Two debris disks, both displaying distinct concentric rings, became focal points for investigation.
One such system, TWA 7, showed three rings, including a particularly narrow one flanked by gaps devoid of matter. Imaging from JWST revealed a distinct signal at the center of this narrow ring. After ruling out observational errors, the team identified it as an exoplanet. Simulations confirmed the planet's gravitational influence, matching both the ring's formation and the voids around it.
The planet, designated TWA 7 b, is roughly equivalent in mass to Saturn-only a tenth the weight of planets previously imaged directly. Its detection marks a breakthrough in observing smaller, Earth-like exoplanets. Researchers believe JWST could eventually detect planets with as little as 10% of Jupiter's mass.
This result underscores the importance of space-based telescopes equipped with advanced coronagraphs. Future missions are already selecting target systems for further exploration using next-generation instruments.
Research Report:Evidence for a sub-jovian planet in the young TWA7 disk
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