2024/11/04 by Rizos, J. L., Farnham, T. L., Kloos, J. +2
#Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2411.01997
We present a comprehensive reassessment of the region containing the large smooth patch on comet 9P/Tempel 1, leveraging data from the Deep Impact and Stardust-NExT missions, an updated stereophotoclinometry-based shape model, and numerical simulations. The study seeks to understand the nature, the triggering mechanism, and the chronology of this distinctive feature. Morphological and spectral analysis reveals that the smooth patch has a thickness of approximately 25 meters, a notable lobate U-shape, and a spectral composition indistinguishable from the surrounding terrain, which favors an endogenous origin. Gravitational flow simulations demonstrate that a single event could have formed the large smooth patch, the secondary smooth units observed on other faces of the comet, and the mass wasting features adjacent to the northern smooth unit. We estimate this event occurred between 600 and 1,000 years ago, a temporal window that notably coincides with a period of abrupt orbital changes caused by multiple close encounters with Jupiter. We propose that the gravitational stresses experienced during these encounters triggered a mass flow, providing the most coherent explanation for the formation and uniqueness of this geological feature on Tempel 1. These shed new light on the geology of cometary nuclei and the role of external dynamic processes in shaping their surfaces.