2008/10/07 by С. И. Ипатов, Michael F. A’Hearn, Ipatov, Sergei I. +1
Physics and Astronomy · #Astro and Planetary Science #Astrophysics (astro-ph) #FOS: Physical sciences #Planetary Science and Exploration #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.0810.1294
openalex publication_date 2008/10/07 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/28
Time variations in velocities and relative amount of observed particles (mainly icy particles with diameter d<3 μm) ejected from Comet 9P/Tempel 1 are studied based on analysis of the images made by Deep Impact (DI) cameras during the first 13 minutes after the collision of the DI impactor with the comet. Analysis of maxima or minima of plots of the time variations in distances of contours of constant brightness from the place of ejection allowed us to estimate the characteristic velocities of particles at several moments in time te of ejection after impact for te ≤ 115 s. Other approaches for estimates of the velocities were also used. All these estimates are in accordance with the same exponential decrease in velocity. The estimates of time variations in the relative amount of ejected particles were based also on results of the analysis of time variations in the size of the bright region of ejected material. At te~10 s, the morphology of the ejecta (e.g. the location and brightness of the brightest pixel) changed and the rate rte of ejection of observed material increased. Between 1 and 3 seconds after the impact and between 8 and 60 seconds after the impact, more small bright particles were ejected than expected from crater excavation alone. An outburst triggered by the impact could cause such a difference. The sharp (by a factor of 1.6) decrease in the rate of ejection at 55