Orbital, Latitudinal, and Diurnal Variations in Meteoroid Influx, Atmospheric Ablation and Ionization, and Micrometeorite Accretion at Venus

This study provides a comprehensive description of the meteoric cycle on Venus, considering the temporal, latitudinal, and orbital variations of meteoroid mass influx before atmospheric entry, the ablation rates and the subsequent ionization of meteoric elements in the upper atmosphere, along with the accretion of micrometeorites at the surface. The study integrates three models: (i) the NASA-GSFC Meteoroid Input Function for Venus, which characterizes the size, velocity, and radiant distributions of the Jupiter-family comets (JFCs), main-belt asteroids, Halley-type comets (HTCs), and Oort-cloud comets (OCCs); (ii) the University of Leeds Chemical Ablation Model, which computes ablation rates of 12 meteoric species based on entry parameters; and (iii) the Electron Linear Density model, which estimates the ionization probabilities from hyperthermal collisions with atmospheric molecules. The total meteoroid mass influx is shown to peak during Venus’ ecliptic crossings (∼31.8 × 10 3 kg Earth-day −1 at the second crossing) and reaches a minimum around the minimum and maximum vertical displacements (∼24.2 × 10 3 kg Earth-day −1 ). The JFCs dominate pre-atmospheric mass input and largely drive variability along Venus’ orbit, while ablation is primarily contributed by the HTCs and OCCs. Ablation exhibits a pronounced diurnal asymmetry at equator, with enhanced injection on the dayside hemisphere around a height of 118 km. Neutral species account for 83.1% of ablated species, while ionization dominates above ∼119 km, particularly for Na and K. JFCs supply ∼90% of micrometeorites deposited at the surface, being the maximum accretion rates of organics at the second crossing between ∼0.3 × 10 3 kg Earth-day −1 (CI-chondrite) and ∼1.7 × 10 3 kg Earth-day −1 (cometary enrichment).