There are four known sources of dust in the inner solar system: Jupiter Family comets, asteroids, Halley Type comets, and Oort Cloud comets. Here we combine the mass, velocity, and radiant distributions of these cosmic dust populations from an astronomical model with a chemical ablation model to estimate the injection rates of Na and Fe into the Earth's upper atmosphere, as well as the flux of cosmic spherules to the surface. Comparing these parameters to lidar observations of the vertical Na and Fe fluxes above 87.5 km, and the measured cosmic spherule accretion rate at South Pole, shows that Jupiter Family Comets contribute (80 ± 17)% of the total input mass (43 ± 14 t d −1 ), in good accord with Cosmic Background Explorer and Planck observations of the zodiacal cloud.

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We report the detection of intense emission from magnesium and iron in Mars' atmosphere caused by a meteor shower following Comet Siding Spring's close encounter with Mars. The observations were made with the Imaging Ultraviolet Spectrograph, a remote sensing instrument on the Mars Atmosphere and Volatile EvolutioN spacecraft orbiting Mars. Ionized magnesium caused the brightest emission from the planet's atmosphere for many hours, resulting from resonant scattering of solar ultraviolet light. Modeling suggests a substantial fluence of low‐density dust particles 1–100 µm in size, with the large amount and small size contrary to predictions. The event created a temporary planet‐wide ionospheric layer below Mars' main dayside ionosphere. The dramatic meteor shower response at Mars is starkly different from the case at Earth, where a steady state metal layer is always observable but perturbations caused by even the strongest meteor showers are challenging to detect.

Article:Cristmani, MMJ, Schneider, NM, Plane, JMC orcid.org/0000-0003-3648-6893 et al. (13 more authors) (2017) Detection of a persistent meteoric metal layer in the Martian atmosphere. Nature Geoscience, 10 (6). pp. 401-404. ISSN 1752-0894 https://doi.org/10.1038/ngeo2958 © 2016 Macmillan Publishers Limited. All rights reserved. This is an author produced version of a paper published in Nature Geoscience. Uploaded in accordance with the publisher's self-archiving policy.eprints@whiterose.ac.uk https://eprints.whiterose.ac.uk/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. 11,14,15,16,17 and all data used herein are available on the NASA Planetary Data System. Detection of a persistent meteoric metal Detection and Variability of Mg +Emission from Mg + was reliably detected in every periapse limb scan obtained over one Mars year (two Earth years; Figures 1, 3) whenever the Mg + layer was appropriately illuminated and the instrument orientation did not introduce excessive scattered solar continuum (for these purposes, stray light). The Mg + emission feature, centered on 280 nm, is due to resonant scattering of solar UV photons rather than direct excitation during ablation. Mg + brightnesses were extracted from a model spectrum fit (Figure 1a,b), using line positions and atomic constants of known emitters in this spectral region plus a stray light solar spectrum 15,16,18 .The Mg + emission brightness was converted to local ion density through an Abel transform, common in the study of optically thin airglow emissions 19 (see SI). The Mg + layer has a mean peak concentration of ~250 cm -3 and is typically found near an altitude of 90 km (Figure 2). Reported altitudes carry a 2.5 km uncertainty consistent with slit averaging in 5 km bins 16 . Figure 3 shows the derived densities in a fixed altitude range over the course of the mission. Brightness measurements carry Poisson random uncertainties propagated through a multiple linear regression technique and Abel transform. In addition, the brightnesses are subject to 30% systematic uncertainty in absolute calibration (not shown in figure error sizes) 14 . The random and systematic uncertainties propagate linearly into densities and other derived quantities.Observations of Mg + density demonstrate ...

The size and velocity distribution of cosmic dust particles entering the Earth's atmosphere is uncertain. Here we show that the relative concentrations of metal atoms in the upper mesosphere, and the surface accretion rate of cosmic spherules, provide sensitive probes of this distribution. Three cosmic dust models are selected as case studies: two are astronomical models, the first constrained by infrared observations of the Zodiacal Dust Cloud and the second by radar observations of meteor head echoes; the third model is based on measurements made with a spaceborne dust detector. For each model, a Monte Carlo sampling method combined with a chemical ablation model is used to predict the ablation rates of Na, K, Fe, Mg, and Ca above 60 km and cosmic spherule production rate. It appears that a significant fraction of the cosmic dust consists of small (<5 µg) and slow (<15 km s −1 ) particles.