A possible explanation for the presence of crystalline H2O-ice on Kuiper Belt Objects

The detection of crystalline H2O-ice on multiple surfaces of Kuiper Belt Objects (KBOs) seems to contrast with what scientists understand about the surface environment of these objects, as previous estimates suggest that radiolysis should have easily amorphized these objects' surface over their lifetimes. Here, we use a detailed laboratory approach to show that crystalline H2O-ice can be amorphized by energetic electrons at temperatures as high as 70 K. However, the estimated time needed to completely amorphize the H2O-ice present on the surface of a KBO to the depth probed by near-infrared spectroscopy is only slightly less than the age of the solar system. Given the uncertainties involved in these types of extrapolations and the possibility of a resurfacing event occurring in these objects lifetime, the detection of crystalline or at least partially crystalline H2O-ice on KBOs should be expected.