calculations. Halley's orbitalperiod has varied between 74 and 80 years since 240 BC. Its orbit around the Sun is highly elliptical, with an orbital eccentricity
mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods
{\sqrt {\mu \over a}}} where v is the orbital velocity, a is the length of the semimajor axis, T is the orbitalperiod, and μ = GM is the standard gravitational
elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several millions of years. Short-period comets
rotation period of Nereid". Monthly Notices of the Royal Astronomical Society. 250: 1P–2P. Bibcode:1991MNRAS.250P...1W. doi:10.1093/mnras/250.1.1p. Jones