Astronomers find 2 gigantic planets lighter than cotton candy: “Comparable to a nice blob of shaving foam”

Astronomers have uncovered a pair of giant planets that are lighter than cotton candy — super-puffs the size of Jupiter.

The featherweight pair — orbiting a star 1,110 light-years away — are the biggest exoplanets found to have less density than cotton candy.

That makes them the lightest known planets of their size, said the University of Oxford’s George Dransfield.

“These two planets have densities comparable to a nice blob of shaving foam, fresh from the can,” Dransfield said in an email. She and her team reported their findings Wednesday in Monthly Notices of the Royal Astronomical Society.

Dransfield suspects these fluffy, wispy worlds are probably white or blue, depending on whether the skies there are cloudy — not shades of cotton-candy pink. The planets are probably mostly hydrogen and helium, although it will take follow-up observations by NASA’s Webb Space Telescope to confirm their chemical makeup.

Detected by NASA’s Tess satellite over the past decade, these two especially puffy puffs orbit a star in the southern constellation Volans, known as the flying fish. The researchers studied the planets’ orbits using telescopes on Earth to determine their density, from 1,110 light-years away. A light-year is nearly 6 trillion miles.

In 2024, researchers found a super-puff planet 1,200 light years from Earth, calling it a “cosmic mystery.”

Jupiter, by comparison, is as much as 35 times denser than these two lightweights.

The newly found planets also have unusually long orbits, with one taking 139 days and the other taking 232 days to circle the host star, NASA said in a news release.

Considered rare in the cosmos, super-puffs are thought to form around the disk of gas and dust around a newborn star where there is more gas than dust. They shed much of the material over time, stripping down even more.

“The main reason these planets are interesting to study is that we didn’t expect to see them at all,” said Jon Jenkins, the science lead for the Science Processing Operations Center at NASA’s Ames Research Center in California’s Silicon Valley. “They represent a puzzle for us to solve about how giant planets like Jupiter and the super-puffs form.”

NASA’s tally of worlds outside our solar system currently stands at nearly 6,300 confirmed. Fewer than 40 are super-puffs, according to Dransfield.

“Ultimately, by studying exotic systems containing rare planet types, we add further pieces to the puzzle of planet formation and learn more about our place in the cosmos,” she said.