Published online by Cambridge University Press: 07 August 2017
The Quadrantid meteor shower has been recognized for more than 150 years. The dynamics of the corresponding stream is peculiar due to the high orbital inclination and, for some particles, the closeness of the 2/1 mean motion resonance with Jupiter. It has been the subject of many investigations relating to the structure of the stream and its nodal retrogression as well as its long-term history and its likely cometary origin. Thus Hamid and Youssef (1963) found that the jovian secular perturbations lead to very large changes in the inclination and perihelion distance of typical stream particles with a period around 4000 yrs. From a more extensive study by Williams et al. (1979) it was obvious that this period is not unique but may vary considerably between different particles. Related to this behaviour is also the investigation by Froeschlé and Scholl (1982) who performed an extensive study of three-dimensional orbits at the 2/1 resonance. The orbits remain confined in the resonance zone and are stable in Hill's sense. Close encounters with Jupiter are avoided through the action of three main protection mechanisms: σ libration around 0, ω libration aroud 90°, and e–ω coupling, although most orbits exhibit large variations in inclination and eccentricity. Investigating in more detail a Quadrantid-like meteor stream, Froeschlé and Scholl (1986) also found a nonuniform nodal retrogression and an unusual progression. This behaviour causes a formation of arcs which was not found for other meteor streams in resonance with Jupiter – however, almost never having large inclinations.