Insights into Luminous Efficiency in Meteoroid Research

Explore luminous efficiency in meteoroid research at the University of Western Ontario, with past work by various researchers spanning different methodologies and materials. Discover the complexities of optical observations and the impact of meteor speed on kinetic energy emitted as light.

• Meteoroid Research
• Luminous Efficiency
• Optical Observations
• University of Western Ontario
• Scientific Studies

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Presentation Transcript

1. 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. 0.06 0.05 Theoretical Optical observations Optical/radar Laboratory Artificial meteors 0.04 Luminous Efficiency (%) 0.03 0.02 0.01 0 0 20 40 60 80 100 Velocity (km/s) Hill et al 2005 Ceplecha&McCrosky 1976 Ayers(stone) 1970 Ayers(Iron) 1970 Opik 1955 constant Verniani 1964 Halliday 1981 Revelle&Rajan 1979 Saidov&Simek 1989 Becker&Slattery 1973 Ceplecha&Revelle 2005 Cook et al 1963 Hill et al. corrected Becker&Friichtenicht1971 Jones&Halliday 2001 Weryk&Brown 2013

4. Past Work 10 1 luminous efficiency, % 0.1 Hill, Rogers, Hawkes (2005) Ceplecha & McCrosky (1976) Verniani (1965) Weryk & Brown (2013) 0.01 0.001 0 10 20 30 40 50 60 70 80 meteor speed, km/s 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 = 0vn n = 1.01 0.15 0 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 = 0vn 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