Free Astronomy Magazine September-October 2024

24 SEPTEMBER-OCTOBER 2024 ASTRO PUBLISHING Eternal sunrises and sunsets on distant world R esearchers using NASA’s James Webb Space Telescope have fi- nally confirmed what models have previously predicted: An exoplanet has differences be- tween its eternal morning and eter- nal evening atmosphere. WASP-39 b, a giant planet with a diameter 1.3 times greater than Jupiter, but simi- lar mass to Saturn orbits a star about 700 light-years away from Earth, is tidally locked to its parent star. This means it has a constant dayside and a constant nightside—one side of the planet is always exposed to its star, while the other is always shrouded in darkness. by NASA/ESA/CSA Hannah Braun Christine Pulliam T he background artist’s concept shows what the exoplanet WASP-39 b could look like based on indirect transit observations from NASA’s James Webb Space Telescope as well as other space- and ground-based telescopes. [NASA, ESA, CSA, Ralf Crawford (STScI)]