Disk of gas observed around what might be youngest exoplanet yet discovered

A Jupiter-mass exoplanet could be the youngest yet discovered, and scientists just observed a disk of gas that could birth the planet’s first moon or moons

Scientists have, for the first time, observed a disk of gas around a young and distant exoplanet. The torus of material orbiting the planet is known as a circumplantery disk, and could one day form moons around the distant exoplanet. The exoplanet may prove to be the youngest exoplanet yet discovered.

A large team of researchers led by University of Wisconsin, Madison professor and astronomer Ke Zhang made the discovery using the Atacama Large Millimeter/submillimeter Array, or ALMA radio telescope in Chile. Researchers had previously used ALMA to detect a circumplanetary disk around a different star in 2019, but that research focused on dust in the disk, rather than gas.

The new finding, published in a paper in the Astrophysical Journal Letters, comes from the star AS 209, located about 395 million light years from Earth. Using ALMA, the researchers found a gap in the protoplanetary disk, a disk of gas and dust orbiting the star from which planets may form.

That gap may correspond to a Jupiter-sized exoplanet, around which the researchers detected a disk of gas, the circumplanetary disk orbiting the planet much the way the protoplanetary disk orbits the host star.

Like a protoplanetary disk, a circumplanetary disk hosts material that may condense into Moons due to gravity over time. Researchers may have caught the process early one — star is estimated to be just 1.6 million years old, which could make the exoplanet one of the youngest ever observed.

But the findings still require further confirmation, confirmation that may be coming soon thanks to the newly operational James Webb Space Telescope.

“The best way to study planet formation is to observe planets while they’re forming,” University of Florida astronomer and lead author of the study Jaehan Bae said in a statement. “We are living in a very exciting time when this happens thanks to powerful telescopes, such as ALMA and JWST.”