New class of gas giants with exceptionally low density
An international consortium of astronomers has reported the detection of two extraordinary exoplanets whose densities fall below that of cotton candy. The objects belong to the rare “super‑puff” category, characterized by an extremely large radius relative to their modest mass.
The study was led by the University of Oxford in partnership with Université Côte d'Azur, the Observatoire de la Côte d'Azur and the University of Birmingham. Findings were published in the peer‑reviewed journal Monthly Notices of the Royal Astronomical Society.
Precise transit timing and radial‑velocity measurements allowed the team to determine the planets' masses and radii. Calculations indicate densities of less than 0.1 g cm⁻³, far lower than typical gas giants and making them some of the lightest planets known.
This discovery challenges existing formation models, which must now account for mechanisms that can produce such highly inflated atmospheres without causing the planets to disperse.
Future observations with space‑based telescopes and ground‑based facilities are planned to probe the atmospheric composition and physical properties of these super‑puff worlds in greater detail.