Representative images and corresponding surface brightness profiles for 67P at four different points in its orbit. From left to right: May 2003, at 2.9 AU post-perihelion, showing high activity and a trail or neck-line of larger particles; June 2004, 4.9 AU post-perihelion, with the nucleus inactive but a clear neck-line; March 2008, 3.4 AU, at the start of visible activity; October 2008, 1.9 AU pre-perihelion, displaying a broad tail.