Fig. 3.
From: Linear and circular polarization of comet C/2009 P1 (Garradd)
Distribution of the intensity (left panel) and degree of circular polarization (right panel) over the coma of comet Garradd on February 14, 2012 (upper panel) and April 21, 2012 (bottom panel) in the red continuum filter 6840/90 Å. The intensity contours are at 0.03, 0.04, 0.06, 0.08, 0.1, 0.15, 0.2, 0.3, 0.4, 0.6, 0.8 of the maximum flux for the two observation dates. The robust average circular polarization in 20-px-wide (~7″ at the comet) circular apertures is shown as a function of the distance from the nucleus of the comet. The angle of 1 arcsec corresponds to 1005 km and 1424 km at the comet on February 14 and April 21, respectively.