2.10.10 Dust Ponding
The close-up observations of (433) Eros by the NEAR spacecraft revealed the
presence of “ponded deposits”. These are flat-floored, smooth surfaces within an
irregularly-rimmed depression. Morphologically, the deposits sharply embay the
bounding depression in which they sit (Dombard et al. 2010) although Roberts
et al. (2014) state that less than half the pond candidates on (433) Eros have clearly
flat floors.
There are several surfaces in the Khepry and Aker regions on 67P that appear to
be similar to ponded deposits (Fig. 2.85). The features on 67P are up to 160 m
diameter and therefore similar in size to those seen on Eros (Roberts et al. 2014). The
Fig. 2.84 Changes in the appearance of the surface of Ma’at through the perihelion passage. (a)
Image acquired on 7 August 2014. (b) The same area acquired on 28 March 2015. Arrows mark
the areas where significant changes have occurred in the smooth terrain. (c) A sub-image of (b)
(marked by the box) shows an exposure of unusual material in a region that previously (image a)
was much smoother in texture. (d) The same sub-image but stretched reveals activity from this
area against a shadowed background (Image numbers: N20140807T232034548ID30F22,
N20150328T161249393ID10F82)
2.10 Surface Appearance and Cometary “Geology”
151
The close-up observations of (433) Eros by the NEAR spacecraft revealed the
presence of “ponded deposits”. These are flat-floored, smooth surfaces within an
irregularly-rimmed depression. Morphologically, the deposits sharply embay the
bounding depression in which they sit (Dombard et al. 2010) although Roberts
et al. (2014) state that less than half the pond candidates on (433) Eros have clearly
flat floors.
There are several surfaces in the Khepry and Aker regions on 67P that appear to
be similar to ponded deposits (Fig. 2.85). The features on 67P are up to 160 m
diameter and therefore similar in size to those seen on Eros (Roberts et al. 2014). The
Fig. 2.84 Changes in the appearance of the surface of Ma’at through the perihelion passage. (a)
Image acquired on 7 August 2014. (b) The same area acquired on 28 March 2015. Arrows mark
the areas where significant changes have occurred in the smooth terrain. (c) A sub-image of (b)
(marked by the box) shows an exposure of unusual material in a region that previously (image a)
was much smoother in texture. (d) The same sub-image but stretched reveals activity from this
area against a shadowed background (Image numbers: N20140807T232034548ID30F22,
N20150328T161249393ID10F82)
2.10 Surface Appearance and Cometary “Geology”
151