TY - JOUR
T1 - The Impact of Comet Siding Spring's Meteors on the Martian Atmosphere and Ionosphere
AU - Crismani, M. M.J.
AU - Schneider, N. M.
AU - Evans, J. S.
AU - Plane, J. M.C.
AU - Carrillo-Sánchez, J. D.
AU - Jain, S.
AU - Deighan, J.
AU - Yelle, R.
N1 - Funding Information: M. C. thanks J. Grebowsky and M. Benna for their insight on metallic ions and Z. Girazian, R. Lillis, L. Andersson, and C. Fowler for helpful discussions about the ionosphere. NASA supports the MAVEN mission through the Mars Scout program. J. M. C. P. and J. D. C-S. were supported by the European Research Council (project 291332-CODITA). All data used herein are available on the Atmospheres node of the NASA Planetary Data System, under periapse level 1c files. The retrieved concentrations presented in this work, from the IUVS periapse data, are available on the MAVEN Science Data Center (SDC) website hosted at LASP https://lasp.colorado.edu/maven/sdc/ public/pages/datasets/iuvs.html. The authors declare no competing financial interests. Publisher Copyright: ©2018. American Geophysical Union. All Rights Reserved.
PY - 2018/10
Y1 - 2018/10
N2 - On 19 October 2014, comet C/2013 A1 (Siding Spring) had a close encounter with Mars and deposited cometary dust particles into the Martian atmosphere. We report a comprehensive analysis of the resulting meteor shower and its perturbation on Mars' atmosphere and ionosphere. Using Mars Atmosphere and Volatile EvolutioN/Imaging Ultraviolet Spectrograph observations of ablated meteoric metallic species, we show this shower lasted less than 3 hr and was therefore limited to one hemisphere. Meteoric ablation occurred in a narrow altitude layer, with Mg+, Mg, Fe+, and Fe deposited between about 105 and 120 km, consistent with comet Siding Spring's relative velocity of 56 km/s. We find that 82 ± 25 t of dust was deposited, improving previous measurements and a thousand times larger than model expectations. With regular observations over two Mars days, we show that horizontal winds globally redistribute this material and also suggest new vertical transport mechanisms for metallic ions. Such transport is inconsistent with diffusion and may be related to electrodynamic processes. The rapid loss of neutral species and presence of ions at high altitudes indicate that our understanding of existing Martian meteoric chemistry modeling and ionospheric dynamics is incomplete.
AB - On 19 October 2014, comet C/2013 A1 (Siding Spring) had a close encounter with Mars and deposited cometary dust particles into the Martian atmosphere. We report a comprehensive analysis of the resulting meteor shower and its perturbation on Mars' atmosphere and ionosphere. Using Mars Atmosphere and Volatile EvolutioN/Imaging Ultraviolet Spectrograph observations of ablated meteoric metallic species, we show this shower lasted less than 3 hr and was therefore limited to one hemisphere. Meteoric ablation occurred in a narrow altitude layer, with Mg+, Mg, Fe+, and Fe deposited between about 105 and 120 km, consistent with comet Siding Spring's relative velocity of 56 km/s. We find that 82 ± 25 t of dust was deposited, improving previous measurements and a thousand times larger than model expectations. With regular observations over two Mars days, we show that horizontal winds globally redistribute this material and also suggest new vertical transport mechanisms for metallic ions. Such transport is inconsistent with diffusion and may be related to electrodynamic processes. The rapid loss of neutral species and presence of ions at high altitudes indicate that our understanding of existing Martian meteoric chemistry modeling and ionospheric dynamics is incomplete.
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U2 - 10.1029/2018JE005750
DO - 10.1029/2018JE005750
M3 - Article
SN - 2169-9097
VL - 123
SP - 2613
EP - 2627
JO - Journal of Geophysical Research: Planets
JF - Journal of Geophysical Research: Planets
IS - 10
ER -