Harrison Nicholls is a researcher in the Department of Physics at the University of Oxford. He led the 2026 study proposing l-98-59-d as the prototype of a new exoplanet class — a sulphur-rich global magma-ocean-world (src-l-98-59-d-sulphur-magma-world-2026-05). Nicholls argues the result demonstrates that current small-planet taxonomy (rocky / gaseous / water-rich) is too coarse.