The structure of $\kappa$ Cygnid and August Draconid meteoroid streams

TL;DR

This study maps and analyzes the structure and orbital dynamics of the $$ Cygnid and August Draconid meteoroid streams using precise fireball data, revealing their resonance with Jupiter and complex radiant structures.

Contribution

It provides detailed orbital and physical characterization of the $$ Cygnid and August Draconid streams, including resonance and radiant structure, based on extensive fireball observations.

Findings

$$ Cygnids are in 5:3 resonance with Jupiter with a 7.12-year period.

August Draconids have an extended radiant with three branches.

Neither shower can be described by a single orbital set.

Abstract

Meteoroid streams can be complex structures shaped by the processes of their formation and subsequent orbital evolution. The first step of their understanding is mapping their current stage. We used precise data from the European Fireball Network to disentangle the situation with meteor showers active in August and having radiants in the Cygnus-Draco area. In total, 179 fireballs observed between 2016-2024 were analyzed. We confirmed that two showers, $\kappa$ Cygnids and August Draconids, are present. The meteoroid swarm producing $\kappa$ Cygnids is locked in the 5:3 main-motion resonance with Jupiter with orbital period 7.12 years and has a limited extent of $\leq$ 90 degrees in mean anomaly. The shower is therefore markedly active only once or twice during each seven-year period. The orbits have wide range of inclinations, 28-44 degrees. There is a correlation between inclination, perihelion distance, and argument of perihelion due to observational selection effects. The radiant area is almost 30 degrees long in declination. August Draconids have even more extended radiant 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.