Releasing Atmospheric Martian Dust in Sand Grain Impacts

Abstract

Emission of dust up to a few micrometer in size by impacts of sand grains during saltation is thought to be one source of dust within the Martian atmosphere. To study this dust fraction, we carried out laboratory impact experiments. Small numbers of particles of about 200\textmu{}m in diameter impacted a simulated Martian soil (bimodal \textit{Mars Global Simulant}). Impacts occurred at angles of $\sim 18^{\circ }$ in vacuum with an impact speed of $\sim 1m/s$. Ejected dust was captured on adjacent microscope slides and the emitted particle size distribution (PSD) was found to be related to the soil PSD. We find that the ejection of clay sized dust gets increasingly harder the smaller these grains are. However, in spite of strong cohesive forces, individual impacts emit dust of 1\textmu{}m and less, i.e. dust in the size range that can be suspended in the Martian atmosphere. More generally, the probability of ejecting dust of a given size can be characterized by a power law in the size range between 0.5\textmu{}m and 5\textmu{}m (diameter).

10 pages, 7 figures; Published by the American Astronomical Society

References in corpus (8)

• A scaling theory for the size distribution of emitted dust aerosols suggests climate models underestimate the size of the global dust cycle
• Electrostatics in wind-blown sand
• Understanding planet formation using microgravity experiments
• Macroscopic Dust in Protoplanetary Disks - From Growth to Destruction
• Saltation under Martian Gravity and its Influence on the Global Dust Distribution
• A dearth of small particles in debris disks: An energy-constrained smallest fragment size
• Wind erosion on Mars and other small terrestrial planets
• Laboratory Impact Splash Experiments to Simulate Asteroid Surfaces

Cited by in corpus (1)

• Ejected Particles after Impact Splash on Mars: Aggregates and Aerodynamics