New discoveries in the field of astronomy reveal the existence of two giant exoplanets that have a surprisingly low density, lighter than cotton candy. These celestial bodies, classified as “super-puffs”, have dimensions comparable to those of Jupiter.
The two extremely light exoplanets orbit a distant star 1,110 light-years from Earth and were confirmed to be the largest ever detected with a density less than that of cotton candy. This characteristic makes them unique in the universe known to date.
George Dransfield, a researcher at the University of Oxford, emphasized that the unusual density of these worlds positions them as the lightest known in their size category. The observation challenges preexisting notions about the formation of massive planets.
“The density of these two planets is similar to that of a large portion of shaving foam, fresh from the packaging,” explained Dransfield in an email communication. She and her team detailed their findings in a study recently published in the journal *Monthly Notices of the Royal Astronomical Society*.
Dransfield hypothesizes that these fluffy, almost ethereal worlds may exhibit white or blue colorings, depending on the presence of cloud systems in their atmospheres, as opposed to the pinkish hues associated with cotton candy. The primordial composition of these exoplanets is probably hydrogen and helium, although additional analyzes are needed, using NASA’s James Webb Space Telescope, to determine their chemical composition.
Spotted by NASA’s Tess spacecraft over the past decade, these two especially voluminous clumps of matter orbit around a star in the southern constellation Volans, popularly known as the Flying Fish. Ground-based astronomers employed telescopes to peer into the orbits of planets and calculate their density, at a distance of 1,110 light-years. It is important to note that one light year is equivalent to approximately 9.5 trillion kilometers.
Challenges in understanding the “cotton candy” planets
An illustration released by NASA features the star TOI-791, which resembles the Sun, in the background on the left, and the two giant planets discovered by the TESS space telescope in its orbit.
In a previous find, dated 2024, scientists identified another super-intense planet about 1,200 light-years from Earth, which was described as a true “cosmic mystery” due to its atypical features.
In a comparative analysis, the planet Jupiter has a density up to 35 times greater than that of these two new celestial bodies with reduced mass. This difference accentuates how unusual the newly discovered exoplanets are.
The more recently found planets are also notable for their exceptionally long orbital trajectories; one of them completes a revolution around its host star in 139 days, while the other takes 232 days, according to a note issued by NASA.
Considered rare cosmic phenomena, “super-puffs” would originate in the disk of gas and dust that surrounds a forming star, in regions where gas is more abundant than dust. Over time, they lose a significant portion of their material, which makes them even lighter and more expanded.
“The main reason we were interested in investigating these planets is that they were not expected to exist,” said Jon Jenkins, chief scientist of the Science Processing Operations Center at NASA Ames Research Center, located in Silicon Valley, California. “They represent a puzzle for us about how gas giant planets, like Jupiter and super-puffs, form,” he adds, highlighting that the discoveries force a reassessment of current models of planetary formation, which did not predict such lightness for such large bodies.
NASA reports confirmation of nearly 6,300 worlds outside our solar system. Of those, less than 40 are classified as “super-puffs,” according to data provided by Dransfield.
“Ultimately, by examining exotic systems that contain unusual types of planets, we add crucial pieces to the complex puzzle of planetary formation and deepen our understanding of our place in the vast cosmos,” concluded the researcher.
