Alfvénic Mach number of the solar wind computed from the WindPredict-AW model along the orbit of comet Lovejoy nears its perihelion. The orbit is viewed from a polar view (top) and from Earth’s view (bottom) in Heliographic Stonyhurst coordinates expressed in cartesian form. The orbital direction is indicated by the black arrow and the Sun as the orange disk. The magnetic field lines connecting the comet’s trajectory to the Sun are shown as black lines. The red segment delimits the portion of the orbit connected to the Sun near the brightening. The red timestamps correspond to the orbital time of the comet, whereas the black timestamps correspond to the arrival time at the surface of Alfvén waves launched from that position in the orbit.