A Multipronged Approach for Determining Meteor Masses
Abstract
Individual meteor mass estimates vary greatly depending on the method of observation and the technique used to calculate the mass. The resulting large uncertainty in the total meteoric mass flux affects the atmospheric community's ability to accurately model densities, composition, and phenomena such as the formation of metal layers. This work describes modeling, experimental, and observational efforts to improve individual mass estimates and address the discrepancy between methods.
Two common tools for remote observation of meteors are incoherent scatter radar and optical cameras. Comparison between radar and optical measurements is often difficult due to low numbers of events observed by both systems. We present mass estimates from a set of 150 meteors observed simultaneously by the MAARSY radar and an optical camera network. Radar masses are estimated using FDTD simulations relating the measured radar cross section to the meteor head plasma density; the method has been validated through a set of dual-radar observations. Optical masses are calculated using the standard photometric mass relationship, relating the meteor's luminosity and velocity along its trajectory, measured by the optical cameras, to the mass loss per unit time. The luminous efficiency, which describes the fraction of a meteoroid's kinetic energy that is converted into light, remains the dominant source of uncertainty for photometric masses. We describe a laboratory experiment to characterize the luminous efficiency using a dust accelerator to simulate meteor ablation. We calculate photometric masses by applying the luminous efficiency results from the experimental campaign. Many of the meteors are captured by multiple cameras; this allows multiple independent optical mass estimates to be made for each event. For both the optical and radar observations, mass estimates are made for the total length of the observation, and for the regime in which both systems are observing the meteor simultaneously. The latter quantity is of interest for determining the mass difference between the two observation systems. Comparing the results of these two methods provides insight into the discrepancy between radar and photometric mass estimates, and in the future can be applied to a broader set of observations to make an estimate of the total mass flux.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.P33C..02T