NASA have put out a press release about observations of the ultra-hot gas-giant WASP-18b by the James Webb Space Telescope.

By measuring the radiation of the planet as it is eclipsed by its host star, once every orbit, the team, led by Louis-Philippe Coulombe, mapped out the heat of the planet’s atmosphere. With WASP-18b being so hot, water vapour is likely disassociated over much of the “day side” of the planet, where it is blasted by the host-star’s radiation. But the sensitivity of JWST allowed it to detect water vapour from cooler regions on the planet’s limbs.