1. Margaret Campbell-Brown University of Western Ontario
Luminous efficiency
Margaret Campbell-Brown
University of Western Ontario

2. Luminous efficiency Fraction of kinetic energy emitted as light
Depends on:
Speed
Composition of meteoroid
Spectral response of detector
Mass

3. Theoretical
Optical observations
Optical/radar
Laboratory
Artificial meteors

4. Past Work
based on Weryk & Brown (2013)

5. Past Work Verniani (1965) Super Schmidt meteors
drag equation + luminous intensity equation  luminous efficiency
361 meteors recorded by the Super Schmidt cameras
Assumed follows τ = τ0vn
n = 1.01 ± 0.15
τ0 is based on one meteor (and ‘confirmed’ by artificial meteor experiments)

6. Past Work Ayers et al. 1970 artificial meteors iron and nickel
Assume follows τ = τ0vn
Maximum speed 8 km/s
n = 1.9 ± 0.4
rescaled in 1976 by Ceplecha & McCrosky

7. Past Work Becker & Friichtenicht (1971) & Becker & Slattery (1973)
lab experiments
Micron-sized projectiles of iron, copper, aluminum, silicon
Not free molecular flow
Up to 40 km/s

8. Past Work Weryk & Brown (2013)
Simultaneous radar (CMOR) and optical (CAMO)
Assume ionization efficiency of Jones (1997) is correct
Suggest that video masses are an order of magnitude smaller than previous work

9. Difficulties
Optical observations: need non-fragmenting meteors, precise decelerations
Theoretical: Excitation cross sections not well known at meteor energies
Radar/optical: need an ionization efficiency
Lab experiments: need to have the right flow regime, range of materials
Artificial meteors: expensive, only low speeds possible