How are Jupiter-family comets different from Halley-type comets?

In the study of comet dynamics, Jupiter-family comets and Halley-type comets are distinguished primarily by their orbital periods, inclinations, and Tisserand parameters ($T$).1

Key Differences

• Orbital Period: Jupiter-family comets have orbital periods shorter than about 20 years, while Halley-type comets have periods ranging between 20 and 200 years.1
• Tisserand Parameter ($T$): This value helps identify comets whose orbits have been perturbed by Jupiter. Jupiter-family comets possess $T$ values between 2.0 and 3.0, whereas Halley-type comets have $T$ values less than 2.0.1
• Orbital Inclination: Jupiter-family comets typically exhibit modest inclinations (up to about 35°) relative to the ecliptic, leading them to be called "ecliptic comets." In contrast, Halley-type comets can have much higher inclinations, including retrograde orbits.1
• Origin: The concentration of Jupiter-family comets near the ecliptic suggests they originate from a flattened source, specifically the Kuiper belt or the scattered disk. The origin of Halley-type comets remains a subject of debate, with theories suggesting they may come from the scattered disk, the Oort cloud, or a combination of both.1