Using ultraviolet data from the NASA/ESA Hubble Space Telescope, astronomers have detected carbon ions — charged particles that interact with magnetic fields — in the magnetosphere of the Neptune-sized exoplanet HAT-P-11b and found that the metallicity of its atmosphere is lower than expected. An artist’s impression of the exoplanet HAT-P-11b with its extended helium atmosphere blown away by the star, an orange dwarf star smaller, but...
