The structure of κ Cygnid and August Draconid meteoroid streams

Abstract

Meteoroid streams can be complex structures shaped by the processes of their formation and subsequent orbital evolution. The first step to understanding them is mapping their current stage. We used precise data from the European Fireball Network to disentangle the situation with meteor showers that are active in August and that have radiants in the Cygnus-Draco area. In total, 179 fireballs observed between 2016 and 2024 were analyzed. We confirmed that two showers, κ Cygnids and August Draconids, are present. The meteoroid swarm producing κ Cygnids is locked in a 5:3 main-motion resonance with Jupiter with an orbital period of 7.12 years, and has a limited extent of ≤90° in the mean anomaly. The shower is therefore markedly active only once or twice during each 7-year period. The orbits have a wide range of inclinations, 28-44°. There is a correlation between the inclination, perihelion distance, and argument of perihelion due to observational selection effects. The radiant area is almost 30° long in declination. August Draconids have even more extended radiants and can be divided into three branches, depending on the position of the perihelion relative to the ecliptic plane. Neither of the showers can be described by a single set of orbital elements. We provide sets of representative orbits and identifications with showers previously reported in the literature. Physical properties of meteoroids and possible parent bodies are also discussed.