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Webb telescope captures first direct image of a new exoplanet in debris disk

James Webb Space Telescope discovers its first exoplanet
The disk around the star TWA 7 recorded using ESO's Very Large Telescope's SPHERE instrument. The image captured with JWST's MIRI instrument is overlayed. We can clearly see the empty area around TWA 7 B in the R2 ring (CC #1). Credit: A.-M. Lagrange and al. - Evidence for a sub-jovian planet in the young TWA7 disk, 2025

The James Webb Space Telescope (JWST) has made it possible to better characterize known exoplanets since it was commissioned in 2022. Thanks to research led by a CNRS researcher at the Observatoire de Paris-PSL associated with the Université Grenoble Alpes, the telescope recently captured the direct image of a previously unknown exoplanet.

This discovery, which is in the journal Nature, is a first for the telescope, and was achieved using a French-produced coronagraph installed on the JWST's MIRI instrument.

Exoplanets are key targets in observational astronomy, as they help better understand how form, including our own. While thousands have been detected indirectly, obtaining images of exoplanets represents a genuine challenge. They are less bright, and seen from Earth are located very near their star; their signal, which is drowned out by that of the star, does not stand out enough to be visible.

To overcome this problem, the CNRS developed, in collaboration with the CEA, a telescopic attachment for the JWST's MIRI instrument–a coronagraph. It can reproduce the effect observed during an eclipse: masking the star makes it easier to observe the objects surrounding it, without them being hidden by its light.

It is this technique that allowed the team led by a CNRS researcher to discover a new exoplanet, the first by the JWST. It is located within a of rocky debris and dust.

Rings in debris disks

Scientists have focused on the most promising targets of observation: a few million years-old systems that can be seen "pole-on," which allows for seeing the disks "from above." The recently formed planets in these disks are still hot, which makes them brighter than their older counterparts.

Low-mass planets are in principle easier to detect in the mid-infrared thermal range, for which the JWST has provided a unique window of observation. Among the disks seen from the front, two drew special attention from researchers, with previous observations revealing concentric ring-like structures within them.

The scientists had until now suspected that these structures resulted from gravitational interaction between unidentified planets and planetesimals. One of the two systems, named TWA 7, has three distinct rings, one of which is especially narrow, and surrounded by two empty areas with almost no matter.

The image obtained by the JWST revealed a source within the heart of this narrow ring. After eliminating the possibility of a potential observation bias, the scientists concluded that it was most probably an exoplanet. Detailed simulations have indeed confirmed the formation of a thin ring and a "hole" at the exact planet's position, which perfectly corresponds to the observations made with the JWST.

What prospects for the future discovery of exoplanets?

Named TWA 7 b, this new exoplanet is ten times lighter than those previously captured in images! Its mass is comparable to Saturn's, which is approximately 30% that of Jupiter, the solar system's most massive planet. This result marks a new step in the research and direct imaging of increasingly small exoplanets, which are more similar to Earth than to the gas giants of the solar system.

The JWST has the potential to go even further in the future. The scientists thus hope to capture images of with just 10% of Jupiter's mass.

This discovery shows the relevance of future generations of space-based and designed to search for , especially with the help of more advanced coronagraphs. The most promising systems are already being identified for these future observations.

More information: Anne-Marie Lagrange, Evidence for a sub-Jovian planet in the young TWA 7 disk, Nature (2025). .

Journal information: Nature

Provided by CNRS

Citation: Webb telescope captures first direct image of a new exoplanet in debris disk (2025, June 25) retrieved 25 June 2025 from /news/2025-06-webb-telescope-captures-image-exoplanet.html
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