A modelling study of the seasonal, latitudinal, and temporal distribution of the meteoroid mass input at Mars:  Constraining the deposition of meteoric ablated metals in the upper atmosphere

Abstract

<p>This study provides a comprehensive description of the deposition of meteor-ablated metals in the upper atmosphere of Mars, accounting for the temporal, vertical, latitudinal, and seasonal distribution. For this purpose, the Leeds Chemical Ablation MODel (CABMOD) is combined with a Meteoroid Input Function (MIF) to characterize the size and velocity distributions of three distinctive meteoroid populations around Mars – the Jupiter-Family Comets (JFCs), main-belt asteroid (ASTs), and Halley-Type Comets (HTCs). These modelling results show a significant midnight-to-noon enhancement of the total mass influx because of the orbital dynamics of Mars, with meteoroid impacts preferentially distributed around the equator for particle with diameters below 2000 µm. The maximum total mass input occurs between the northern winter and the first crossing of the ecliptic plane with 2.30 tons sol<sup>-1</sup>, with the JFCs being the main contributor to the overall influx with up to 56% around the Mars equator. Similarly, total ablated atoms mainly arise from the HTCs with a maximum injection rate of 0.71 tons sol<sup>-1</sup> spanning from the perihelion to the northern winter. In contrast, the minimum mass and ablated inputs occur between the maximum vertical distance above the ecliptic plane and the aphelion with 1.50 and 0.42 tons sol<sup>-1</sup>, respectively. Meteoric ablation occurs approximately in the range altitude between 100 and 60 km with a strong midnight-to-noon enhancement at equatorial latitudes. The eccentricity and the inclination of Mars’ orbit produces a significant shift of the ablation peak altitude at high latitudes as Mars moves towards, or away, from the northern/southern solstices.</p>