Astronomers Discover Fluffy Exoplanets with Low Density

Astronomers have identified two incredibly large exoplanets with densities lower than cotton candy. These “super-puffs,” comparable in size to Jupiter, orbit a star approximately 1,110 light-years away. This discovery marks them as the least dense planets of their size ever found.

According to George Dransfield from the University of Oxford, the newly found planets possess densities similar to that of a fresh blob of shaving foam. Dransfield and her team documented their discovery in the Monthly Notices of the Royal Astronomical Society.

Dransfield speculates that these planets may appear white or blue, influenced by the potential cloudiness of their atmospheres. Primarily composed of hydrogen and helium, further investigation using NASA’s Webb Space Telescope is necessary to confirm their chemical composition. Detectives of NASA’s Tess satellite, these puffy worlds orbit a star in the southern constellation Volans, known as the flying fish.

Earth-based telescopes were employed to analyze the planets’ orbits and determine their densities from the vast distance of 1,110 light-years. With one light-year equating to nearly 6 trillion miles (9.7 trillion kilometers), the comparison highlights Jupiter’s density, which is up to 35 times greater than these two exoplanets.

Super-puffs like these are scarce in the universe. They are believed to form within a gas and dust disk around a young star, where gas dominates. Over time, they shed much of this material. Currently, NASA has confirmed nearly 6,300 exoplanets, with fewer than 40 categorized as super-puffs.

Dransfield emphasizes that the study of exotic systems with rare planet types enriches our understanding of planet formation and our place in the universe.

Note: The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation.