Institution(s): 1. US Naval Research Laboratory
In November 2013, the astronomy community was gripped with anticipation as sungrazing comet C/2012 S1 (ISON) made a spectacular and unprecedented close encounter with the Sun. Comet ISON held the potential of being a spectacular nighttime object for terrestrial observers, but its fate hinged on surviving a perilous journey that would take it to within just 1.1-million kilometers of the solar surface. To the great disappointment of a global audience, the comet did not survive, fading rapidly in the hours surrounding perihelion and disappearing from sight soon thereafter. In this talk, I will begin by briefly recapping some of the background regarding ISON, and highlight the main points of interest during its well-observed final year of approach to the Sun. For the majority of the talk I will focus specifically on the final few days and hours of the comet’s passage, during which time it was observed continuously and almost exclusively by a fleet of solar-observing spacecraft. Using these observations and supplemental modeling evidence, I will demonstrate that we are now able to paint a coherent and very compelling picture of how, why, and when, comet ISON was catastrophically destroyed as it approached the Sun on Thanksgiving Day, 2013.