Motion of the Geminid geocentric radiant. Right ascension (panel a), declination (panel b), and velocity (panel c) are plotted as a function of solar longitude (all in equinox J2000.0) for individual meteoroids with formal error bars. The data fit is plotted as a dotted line and the corresponding equation is inserted (no change of velocity with solar longitude was assumed). The motion of the mean radiant as reported by authors cited in the IAU Meteor Data Center is plotted by solid lines as follows: 1 – Dutch Meteor Society data (see Jopek et al. 2003); 2 – Brown et al. (2008a); 3 – SonotaCo (2009); 4 – Brown et al. (2010); 5 – Jenniskens et al. (2016a).