How do you identify short and long term comets

A second important difference between comets coming from the Kuiper Belt and from the Oort cloud is represented by their different characteristic periods.
In fact, short period comets are thought to generate in the Kuiper belt and have rather predictable orbits with short periods (up to 200 years). There are two major families of short period comets: the Jupiter family with periods of less than 20 years and the Halley family with periods form 20 to 200 years. That's short