Overview
- JWST measured about 1,800°C on the planet’s dayside, far below the roughly 2,700°C expected for a bare rock under similar irradiation.
- Researchers infer a thick, volatile-rich atmosphere likely sustained by dynamic exchange with a global magma ocean.
- The result relies on NIRSpec secondary-eclipse observations from Webb GO Program 3860, which monitored the system continuously for over 37 hours.
- The evidence challenges prevailing models that predict ultra-short-period rocky planets should not retain substantial atmospheres.
- TOI-561 b orbits an ancient, iron-poor thick-disk star roughly 280 light-years away, and the team is now mapping temperatures and probing atmospheric composition.