Definition
A short-period comet is a celestial object made of ices and dust, whose orbit around the Sun lasts less than two hundred years. These comets often belong to two main families by orbital inclination: the Jupiter family and the Halley family.
Structure
The internal structure contains a solid nucleus mixing volatile ices, mineral dust, and organic compounds. Around it lies a porous surface that sublimates when approaching the Sun. The coma and tail reform at each perihelion passage.
Orbital behavior
Their motion is governed by solar gravity, influenced by the giant planets. Jupiter-family comets have short, low-inclination orbits, often perturbed by this massive planet. The Halley type shows stronger inclinations and more extended orbits.
Evolution
During their repeated passages, the surface of short-period comets changes due to progressive loss of volatile substances. Their activity weakens over time, and some may evolve into inactive objects similar to asteroids.
Limits and origin
Most short-period comets come from the Kuiper Belt, where icy bodies are displaced by gravitational resonances. Their active life is limited by successive erosion and the depletion of volatile reserves.