A guide to periodic comets
What is a short-period comet, and how long do they take to orbit the Sun?
Comets travel in huge elliptical orbits that take them in close to the Sun and then far out into the distant Solar System.
As they approach the Sun, the powerful energy of our host star heats these rocky ice balls, causing the release of dust and gas and producing a comet tail that can be seen with the naked eye from Earth or captured in astrophotos.
Short-period - or periodic comets - are comets with an orbital period of less than 200 years.
They have much smaller orbits than long-period comets - whose orbits might last 1 million years - and sometimes only take years or decades to make one orbit of the Sun.
Perhaps the most famous short period comet is Halley's Comet, which orbits the Sun every 75 years and can be seen with the naked eye.
More recently, Comet 67P/Churyumov-Gerasimenko has been thrust into the spotlight following the success of the European Space Agency's Rosetta mission.
Other famous short-period comets include Comet Encke, Comet Swift-Tuttle and Comet Giacobini Zinner.
For more on famous comets, read our guide to the best comets of recent times.
Short period comets
While the terms 'short-period' and 'long-period' comets are still used, as is often the case in astronomy, these distinctions have become more refined the more astronomers have learned about comets and their place in the Solar System.
Nowadays, short-period comets are generally divided up into Jupiter-family comets and Halley-type comets.
Jupiter-family comets are short-period comets that complete an orbit of the Sun in less than 20 years.
Their orbits are mainly influenced by the gravitational pull of gas giant Jupiter. Jupiter-family comets are thought to orbit in the Kuiper belt.
As is perhaps obvious given their name, Halley-type comets are short-period comets that have a slightly longer orbit, more like their famous cometary namesake.
Halley-type comets have orbital periods between 20 and 200 years and they are thought to originate further out, in the Oort Cloud.
Below is a selection of images of short-period comets captured by comet-watchers and astrophotographers.