Astronomers have used the unprecedented sensitivity of the Mid-Infrared Instrument (MIRI) onboard the NASA/ESA/CSA James Webb Space Telescope in the thermal infrared to search for exoplanets in the three-ring debris disk around the 6.4-million-year-old star TWA 7.
This Webb/MIRI image shows the Saturn-mass exoplanet TWA 7b. Image credit: NASA / ESA / CSA / Webb / A.M. Lagrange / M. Zamani, ESA & Webb.
Debris disks filled with dust and rocky material are found around both young and older stars, although they are more easily detected around younger stars as they are brighter.
They often feature visible rings or gaps, thought to be created by planets that have formed around the star.
TWA 7 is a young, low-mass (0.46 solar masses) M-type star located about 111 light-years away in the constellation of Antlia.
Also known as CE Antilae or TYC 7190-2111-1, the star is a member of the TW Hydra association.
Its nearly face-on three-ring debris disk made it an ideal target for Webb’s high-sensitivity mid-infrared observations.
“Our observations reveal a strong candidate for a planet shaping the structure of the TWA 7 debris disk, and its position is exactly where we expected to find a planet of this mass,” said Dr. Anne-Marie Lagrange, an astronomer at the Observatoire de Paris-PSL, the Université Grenoble Alpes and CNRS.
Using the coronagraph on Webb’s MIRI instrument on June 21, 2024, Dr. Lagrange and colleagues carefully suppressed the bright glare of the host star to reveal faint nearby objects.
This technique, called high-contrast imaging, enables astronomers to directly detect planets that would otherwise be lost in the overwhelming light from their host star.
After subtracting residual starlight using advanced image processing, a faint infrared source was revealed near TWA 7, distinguishable from background galaxies or solar system objects.
The source is located in a gap in one of three dust rings that were discovered around TWA 7 by previous ground-based observations.
Its brightness, color, distance from the star, and position within the ring are consistent with theoretical predictions for a young, cold, Saturn-mass planet sculpting the surrounding debris disk.
“This observatory enables us to capture images of planets with masses similar to those in the solar system, which represents an exciting step forward in our understanding of planetary systems, including our own,” said Dr. Mathilde Malin, an astronomer at Johns Hopkins University and the Space Telescope Science Institute.
The team’s initial analysis suggests that the object, named TWA 7b, could be a young, cold exoplanet with a mass around 0.3 times that of Jupiter (100 Earth masses) and a temperature near 320 K (roughly 47 degrees Celsius).
Its location (about 52 AU from the star) aligns with a gap in the disk, hinting at a dynamic interaction between the planet and its surroundings.
Once verified, this discovery would mark the first time a planet has been directly associated with sculpting a debris disk and could offer the first observational hint of a Trojan disk — a collection of dust trapped in the planet’s orbit.
“The findings highlight Webb’s ability to explore previously unseen, low-mass planets around nearby stars,” the astronomers said.
“Ongoing and future observations will aim to better constrain the properties of the candidate, verify its planetary status, and deepen our understanding of planet formation and disk evolution in young systems.”
“This preliminary result showcases the exciting new frontier that Webb is opening for exoplanet discovery and characterization.”
The discovery is described in a paper in the journal Nature.
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A-M. Lagrange et al. Evidence for a sub-Jovian planet in the young TWA 7 disk. Nature, published online June 25, 2025; doi: 10.1038/s41586-025-09150-4
