The Low-Density Hydrogen Envelope of Gas Giant WASP-131b
Located approximately 800 light-years away in the constellation Cetus , WASP-131b represents one of the most extreme examples of a low-density gas giant ever identified. As a "puffy" exoplanet, it possesses a mass roughly one-third that of Jupiter but with a physical radius significantly larger, resulting in an exceptionally low bulk density that challenges standard models of planetary formation and gas accretion . Atmospheric Composition and Thermal Structure The atmosphere of WASP-131b is dominated by light elements, primarily hydrogen and helium, which have been expanded significantly by the intense radiative flux from its host star. Observations indicate that the planet experiences high equilibrium temperatures , driving rapid vertical mixing and the formation of high-altitude clouds composed of exotic condensates . Unlike the decaying orbit dynamics seen in tighter systems, WASP-131b occupies a relatively stable, short-period orb...