Experimentally Derived Luminous Efficiencies for Aluminum and Iron at Meteoric SpeedsOPEN ACCESS 

L. K. Tarnecki, R. A. Marshall, J. Fontanese, Z. Sternovsky, T. Munsat

Geophysical Research Letters
First published: 04 April 2023


“Calculating meteoroid masses from photometric observations relies on prior knowledge of the luminous efficiency, a parameter that is not well characterized; reported values vary by several orders of magnitude. We present results from an experimental campaign to determine the luminous efficiency as a function of mass, velocity, and composition. Using a linear electrostatic dust accelerator, iron and aluminum microparticles were accelerated to v > 10 km/s and ablated, and the light production measured. The luminous efficiency of each event was calculated and functional forms fit for each species. For both materials, the luminous efficiency is lowest at low velocities, rises sharply, then falls as velocity increases. However, the exact shape and magnitude of the curve is not consistent between the materials. The difference between the luminous efficiencies for iron and aluminum, particularly at high velocities, indicates that it is not sufficient to use the same luminous efficiency for all compositions and velocities.”

“Key Points

  • Improved laboratory ablation experiments characterize luminous efficiencies of iron and aluminum at velocities greater than 10 km/s
  • Empirical curve fits are derived to relate the luminous efficiency and particle velocity for both species
  • Differences in iron and aluminum results indicate that the luminous efficiency varies with composition”