Key Characteristics:

• Composition: Primarily ice, dust, and small rocky particles.
• Orbit: Comets have highly elliptical orbits that take them close to the Sun and then far into the outer reaches of the solar system.
• Coma: As a comet approaches the Sun, the ice sublimates (turns directly into gas), creating a glowing atmosphere called a coma.
• Tail: Solar radiation and solar wind can push dust and gas away from the coma, forming a tail that always points away from the Sun.
• Nucleus: The solid, central part of a comet.

Types of Comets:

• Short-Period Comets: These comets have orbital periods of less than 200 years and originate from the Kuiper Belt, beyond the orbit of Neptune.
• Long-Period Comets: These comets have orbital periods of thousands of years or more and are believed to come from the Oort Cloud, a distant region surrounding the solar system.

For further information, you can refer to these resources:

• NASA - Comets
• Space.com - Comets: Facts About the 'Dirty Snowballs' of Space