What subject did Queen guitarist Brian May study for his doctoral research?

Brian May studied astrophysics for his doctoral research.

Before Queen became internationally successful, May studied mathematics and physics at Imperial College London. He completed a bachelor of science degree and began doctoral research on reflected light from interplanetary dust and the motion of dust in the Solar System.

His research was interrupted as Queen's music career expanded during the 1970s. May eventually returned to the subject decades later and completed his thesis at Imperial College. He was awarded a PhD in astrophysics in 2007.

The qualification is sometimes described loosely as a degree in astronomy, but astrophysics is the more specific field associated with his doctoral work. May has continued to discuss astronomy publicly and has collaborated with scientists on astronomical projects, including work connected with NASA's New Horizons mission.