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Researchers See Gas Swirling Around a Growing Baby Planet

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WISPIT 2b
A Very Large Telescope image of the planet WISPIT 2b orbiting in a gap in the disk around its host star. [ESO/R. F. van Capelleveen et al.; CC BY 4.0]

Astronomers seem to find something new every time they point a telescope at WISPIT 2, a 5-million-year-old solar-mass star located 430 light-years away. New high-resolution radio observations provide the best view yet of how the young planets of this system interact with the disk that feeds them.

Detecting Distant Planets

In 2025, astronomers carrying out the WIde Separation Planets In Time (WISPIT) survey — a targeted search for widely separated giant planets around young Sun-like stars — revealed a dusty disk surrounding the star WISPIT 2. Orbiting within this disk is a 4.9-Jupiter-mass planet, WISPIT 2b, at 57 au from the star. This makes WISPIT 2 just the second star to host a confirmed, directly imaged planet within its protoplanetary disk. Even more remarkable, WISPIT 2b was detected in Hα, showing that the planet is still growing by accreting gas from the disk.

Later observations confirmed the presence of a second planet, WISPIT 2c, which has an estimated mass of 8–12 Jupiter masses and orbits the star at 15 au. On top of these planetary discoveries, researchers have also found that WISPIT 2 is two stars rather than one!

Best View Yet of the WISPIT 2 System

observations of WISPIT 2 showing the disk in three different ways

New observations of WISPIT 2 from ALMA (left and center panels) and previous observations from the Very Large Telescope (right panel). The star is shown by the small dot at the very center, and the planets are indicated by the two white circles. Click to enlarge. [Adapted from Benisty et al. 2026]

Now, a team led by Myriam Benisty (Max Planck Institute for Astronomy) has presented new high-resolution observations of the WISPIT 2 system from the Atacama Large Millimeter/submillimeter Array (ALMA). These observations show the distribution of gas and large dust particles within the disk. When combined with existing observations of small dust grains, the new data demonstrate how these components of the disk interact with each other and with the system’s planets.

The distribution of gas within the disk, traced by emission from carbon monoxide, roughly follows the pattern seen in previous observations of small dust grains: the orbits of WISPIT 2b and 2c are depleted of gas and dust, demonstrating how the young planets have carved their own berths within the disk, creating a gap at WISPIT 2b’s orbit and a cavity around the star.

dust continuum emission around WISPIT 2 showing the location of a faint dust ring

The left panel shows the dust continuum emission zoomed in on the star (plus sign) and planets (circles). The dotted line shows the location of a faint ring, which is modeled in the center panel. The right panel shows the residuals. Click to enlarge. [Benisty et al. 2026]

The new observations of larger dust particles show a bright ring of emission well outside the orbits of both planets, plus a faint ring in between the two planets that is newly detected in dust continuum emission. This faint ring lines up with a ring in both the gas and small dust grain data, showing that dust and gas are able to journey inward from the outer disk, past the orbit of WISPIT 2b. However, there is no gas or dust detected interior to WISPIT 2c’s orbit, and WISPIT 2c does not appear to be accreting, suggesting that this material is unable to move inward to WISPIT 2c’s orbit and beyond.

Spiral Wakes Making a Splash

velocity field showing gas swirling around WISPIT 2b

Velocity field showing the gas swirling around WISPIT 2b, which is indicated by the green circle farther from the star. [Benisty et al. 2026]

The new ALMA observations allowed Benisty and coauthors to analyze how WISPIT 2b is interacting with the disk. Kinematic maps of the disk showed that the typical emission pattern of a rotating disk is interrupted near WISPIT 2b. The team determined that this feature is due in part to spiral wakes driven by the planet as it orbits within the disk, with potential contributions from local heating or a circumplanetary disk.

Spiral wakes have been spotted in other protoplanetary disks, but this is the first time researchers have been able to definitively associate this feature with a planet rather than other causes, such as gravitational instabilities. Looking ahead, future high-resolution spectroscopic observations of WISPIT 2b and its surroundings will offer researchers an unprecedented opportunity to compare the properties of the planet and its spiral wake against the predictions of simulations — advancing toward a powerful new way to study exoplanets embedded in protoplanetary disks.

Citation

“Mapping the WISPIT 2 Planet-Hosting Cavity at Sub-Hill-Radius Scales,” Myriam Benisty et al 2026 ApJL 1009 L32. doi:10.3847/2041-8213/aea214