VOLANS — Astronomers have discovered two giant exoplanets orbiting the star TOI-791, situated 1,110 light-years away in the southern constellation Volans. These planets are among the lightest and least dense ever found, with densities lower than that of cotton candy.

NASA's TESS satellite detected the two planets. Subsequently, researchers utilized telescopes on Earth to study the planets' orbits and determine their density. University of Oxford researcher George Dransfield stated that these planets are the lightest known of their size. Dransfield and her team reported their findings in Monthly Notices of the Royal Astronomical Society.

The two planets are the biggest exoplanets discovered with a density lower than cotton candy. Dransfield suspects the planets are likely white or blue rather than pink. These planets are likely composed mostly of hydrogen and helium. Jupiter is up to 35 times denser than these newly discovered planets.

One of the newly discovered planets completes an orbit of its host star in 139 days. The other newly discovered planet orbits its host star in 232 days. Dransfield stated that fewer than 40 confirmed exoplanets are super-puffs. Scientists believe super-puff planets may form in the gas and dust disk surrounding a newborn star where gas is more abundant than dust.

Jon Jenkins, Science Lead at NASA Ames Research Center, noted the unexpected nature of these planets. "The main reason these planets are interesting to study is that we didn't expect to see them at all," Jenkins said. "They represent a puzzle for us to solve about how giant planets like Jupiter and the super-puffs form."

"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," Dransfield said. NASA has confirmed nearly 6,300 exoplanets to date.

Follow-up observations conducted by NASA's Webb Space Telescope are required to confirm the chemical makeup of the planets. Dransfield stated, "These two planets have densities comparable to a nice blob of shaving foam, fresh from the can."