Uncertainties in MARS Meteor Orbit Radar Data

Abstract

The uncertainties in meteor radar data and the problem of hyperbolic meteors are interconnected. Meteor orbital data, obtained by the Meteor Automatic Radar System (MARS) at the Kharkiv Institute of Radio Electronics, Ukraine, was used to develop the algorithm to determine the uncertainties of the orbital elements obtained by radar systems such as MARS. We have constructed the empirical model of the distribution of uncertainties in the orbital elements of meteor radar data. MARS had a high effective sensitivity (the limiting magnitude of observed meteors was close to 12 ^ M) and was capable to carry out comprehensive geophysical and astronomical studies of meteors. When we register meteor numbers, radiants, meteoroid velocities, we can talk about astronomical observations. The main objective of meteor astronomy research is to determine the orbit of the meteoroid, in other words, to study a meteoroid as an astronomical object of the Solar System. Sometimes meteoroids may have an interstellar origin. Such meteoroids usually have hyperbolic orbits (i.e. with eccentricities e>1). However, hyperbolic orbits of meteoroids may have another origin, e.g. arise due to errors of observations (primarily due to the errors of eccentricities – σe). To correctly interpret the astronomical data, it is necessary to know how the errors are calculated. In this paper, we estimated the uncertainties in the Kharkiv meteor radar data (the average σe ~0.2) and discussed their connection to the problem of hyperbolic meteors. We obtained ~0.8% of total number of meteoroid orbits in 1975, which we named “real” hyperboles, i.e. with eccentricities more or equal 1+2σe.