The micrometeorite flux at Dome C (Antarctica), monitoring the accretion of extraterrestrial dust on Earth

• Published in: Earth and Planetary Science Letters
• Main Authors: Rojas, J, Duprat, J, Engrand, C, Dartois, E, Delauche, L, Godard, M, Gounelle, M, Carrillo-Sánchez, J, Pokorný, P, Plane, J
• Other Authors: Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), DIM-ACAV, DIM-ACAV+, CNES, LabEx P2IO, PNP/INSU, NASA ISFM, ANR-18-CE31-0011,COMETOR,Origine de la poussière cométaire(2018)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDU]Sciences of the Universe [physics]; Concordia Station; Jupiter; Antarc*; Antarctica
• Online Access: https://hal.science/hal-03148838; https://hal.science/hal-03148838/document; https://hal.science/hal-03148838/file/Rojas_2021_Flux_MMs.pdf; https://doi.org/10.1016/j.epsl.2021.116794

International audience The annual flux of extraterrestrial material on Earth is largely dominated by sub-millimetre particles. The mass distribution and absolute value of this cosmic dust flux at the Earth's surface is however still uncertain due to the difficulty in monitoring both the collection efficiency and the exposure parameter (i.e. the area-time product in m 2 .yr). In this paper, we present results from micrometeorite collections originating from the vicinity of the CONCORDIA Station located at Dome C (Antarctica), where we performed several independent melts of large volumes of ultra-clean snow. The regular precipitation rate and the exceptional cleanliness of the snow from central Antarctica allow a unique control on both the exposure parameter and the collection efficiency. A total of 1280 unmelted micrometeorites (uMMs) and 808 cosmic spherules (CSs) with diameters ranging from 30 to 350 μm were identified. Within that size range, we measured mass fluxes of 3.0 μg.m −2 .yr −1 for uMMs and 5.6 μg.m −2 .yr −1 for CSs. Extrapolated to the global flux of particles in the 12-700 μm diameter range, the mass flux of dust at Earth's surface is 5, 200 ± 1500 1200 tons.yr −1 (1, 600 ± 500 and 3, 600 ± 1000 700 tons.yr −1 of uMMs and CSs, respectively). We indicate the statistical uncertainties expected for collections with exposure parameters in the range of 0.1 up to 10 5 m 2 .yr. In addition, we estimated the flux of altered and unaltered carbon carried by heated and un-heated particles at Earth's surface. The mass distributions of CSs and uMMs larger than 100 μm are fairly well reproduced by the CABMOD-ZoDy model that includes melting and evaporation during atmospheric entry of the interplanetary dust flux. These numerical simulations suggest that most of the uMMs and CSs originate from Jupiter family comets and a minor part from the main asteroid belt. The total dust mass input before atmospheric entry is estimated at 15,000 tons.yr −1. The existing discrepancy between the flux data and the model for ...