The Sporadic Meteoroid Environment: Radar and Optical Fluxes

Sporadic meteoroids come from comets, asteroids and even outside the solar system, and cannot be directly associated with a parent body. Understanding their origins gives us insight to the distribution, composition and history of their parent bodies. More practically, knowing their spatial density, speed and mass distribution helps to assess the threat to spacecraft in Earth orbit and on interplanetary missions. Recent meteor radar data, obtained with the Canadian Meteor Orbit Radar, has provided the most complete picture of the orbital distribution of meteoroids at the Earth and how that distribution changes with solar longitude. Meteor radars, however, suffer from a significant number of observing biases which are not currently well constrained. Optical systems have many fewer biases, but the collection and analysis of data has been much more labour intensive than in the past. In this work, we present a rigorous method for calculating the collecting area of a two-station video system, and apply the method to calculating the flux of meteoroids from the major sporadic sources. The method is tested on meteor showers, where the activity is better constrained. Fig. 1: Density of radiants of orbits observed with the Canadian Meteor Orbit Radar, 2002 - 2008. Each pixel represents the number of orbits in a 2x2 degree bin, in sun-centered ecliptic coordinates.