At solar phase angles less than 0.1 deg, some icy bodies exhibit an extraordinary opposition surge, suddenly brightening by 50% at near zero phase. Verbiscer et al  observed this phenomena for the icy Galilean satellites Mimas, Enceladus, Tethys, Dione, and Rhea and suggest the surge results from the light-scattering properties of freshly resurfaced icy regoliths. Buratti et al  and Earle et al  observed a similarly sharp opposition surge on Neptune's icy satellite Triton, which is known to have active cryovolcanoes. Here we examine the solar phase curves of 9 Trans-Neptunian Objects that we have measured at phase angles smaller than 0.1 deg (Rabinowitz et al , Schaefer et al ), including previously unpublished observations 1997 CS29 and 2005 UJ438. This sample includes hot and cold classical Kuiper-Belt objects, Plutinos, Centaurs, and three binary TNOs. Of all these targets, only 1997 CS29 has a sharp surge at near zero phase, and a nearly flat phase curve at large angles. Since this target is also a binary with an unusually large and close companion , we suggest that both 1997 CS29 and its companion have been resurfaced by each other's impact ejecta via the mechanism proposed by Stern , with fresh surface material producing the opposition spike. Verbiscer, A., et al. 2007, Science, 315, 815;  Buratti, B. et al. 2007, Workshop on Ices, Oceans, and Fire: Satellites of the Outer Solar System, Boulder Colorado;  Earle, D., et al. 2008, BAAS, 40, 480;  Rabinowitz, D. et al. 2007, AJ, 133, 26;  Schaefer, B., et al. 2009, AJ, 137, 129;  Stephens, D. & Knoll, K. 2006, AJ, 131,1142; Stern, S. A. 2009, Icarus, 199, 571.
AAS/Division for Planetary Sciences Meeting Abstracts #41
- Pub Date:
- September 2009