Researchers from the University of Liege in Belgium report an extraordinary exoplanet named WASP-193b, located roughly 1.2 thousand light years from Earth. The planetary body stands out because its density is astonishingly close to that of cotton candy, a clue that challenges established models of gas giant formation. The findings were published in a peer reviewed astronomy journal.
WASP-193b measures about half again larger than Jupiter, yet its mass is only a tenth of that of Jupiter. The planet orbits its Sun-like host star, WASP-193, at a brisk pace, completing a full revolution every 6.25 days. This tight orbit contributes to the extreme atmospheric expansion scientists observe on the world.
An ultra low density of 0.059 grams per cubic centimeter sets WASP-193b apart from more than five thousand confirmed exoplanets. Even if a hypothetical core were absent, such a low density remains difficult to reconcile with standard theories of giant planet formation, prompting a reevaluation of how gas giants can develop in close stellar environments.
For context, Earth has a density of 5.51 grams per cubic centimeter, while Jupiter sits at 1.33 grams per cubic centimeter. Cotton candy, by comparison, weighs in at roughly 0.05 grams per cubic centimeter. The stark contrast helps scientists gauge the extreme nature of WASP-193b and the unusual physics at play in its atmosphere.
Experts suggest the planet’s proximity to its star drives the inflation of its hydrogen and helium atmosphere. This heating and expansion likely reduce overall density, producing the remarkable puffiness observed from Earth’s vantage point. The discovery adds a striking data point to the study of how stellar radiation can sculpt the outer layers of giant planets.
Earlier observations had already identified another exoplanet with similarly low density, underscoring a growing interest in how such worlds form and evolve. The ongoing work on WASP-193b invites astronomers to refine models of planetary atmospheres and to consider scenarios where intense stellar irradiation reshapes a planet’s structure in surprising ways.
These findings come as part of a broader effort to chart the diversity of planets beyond our solar system. By examining extreme cases like WASP-193b, scientists aim to map the range of possible planetary configurations and to better understand the processes that govern planet formation across different stellar environments. The study highlights the value of precise measurements of mass, radius, and atmospheric composition to unlock the physics behind these distant worlds. The observation team continues to monitor WASP-193b, seeking additional clues about its history and the dynamical forces that keep it in such a close orbit around its sunlike star.