That depends on what you call 'long' or 'short'.
Halley's period is in the neighborhood of 75 years, give or take a few years.
Since that's short enough for two perihelions to occur within a single human lifetime,
I guess it ought to be considered a short period.
Somewhere within the orbit of Mars and Jupiter solar radiation becomes strong enough for the comet to vent gas. Comets are comprised largely of frozen carbon dioxide (CO2) which sublimates directly to gas, and water ice (H2O) which also steams off in the sunlight. This is what creates the comet's coma and tail. The tail is formed by the solar wind blowing bits of comet out away from the sun.
Long period comets make far fewer close passes towards the sun, so material is ablated over much less frequently.
Long period comets take a long time to come back around, while short-period comets only take a short time. Where's the cutoff? About 200 years. So a comet like Hale-Bopp, that won't come back into the inner solar system for another 2500 years, is a long period comet, while Halley's Comet (every 76 years) is a short-period comet.
Well this is my answer, because there is always a difference between long and short.
Long term comet
comet shoemaker is aredy gone, it does not have a period.
A comet with a period of 200 years or more.
Halley's Comet was a periodic comet; it returns to the inner system every 76 years. Hale-Bopp is a very long-period comet; it may have been last seen in 2215 BC. That may have been Hale-Bopp's first approach to the Sun; its orbit was likely altered by close brushes with Jupiter then, and again during its last pass in 1997. Hale-Bopp's next appearance may be in or around the year 4530 AD.
600,000,000,000,000,000,000,000,000,000
Long-period comets have periods of over 200 years.The longest would probably be somewhere around a million years (comparable to the orbital periods of objects in the Oort cloud); much longer than that, and it will go away far enough to be captured by the gravitational field of other stars.
comet shoemaker is aredy gone, it does not have a period.
Not more than 200 years - less than 200 years. As to the "why", that's because this is how "short-period" vs. "long-period" is defined. Any comet that takes less than 200 years for one revolution is defined as short-period.
A comet with a period of 200 years or more.
A comet with a period of 200 years or more.
a long term comet is over 1 year a short term comet is from 0-3 months
Long period comet
Halley's Comet was a periodic comet; it returns to the inner system every 76 years. Hale-Bopp is a very long-period comet; it may have been last seen in 2215 BC. That may have been Hale-Bopp's first approach to the Sun; its orbit was likely altered by close brushes with Jupiter then, and again during its last pass in 1997. Hale-Bopp's next appearance may be in or around the year 4530 AD.
Comet (C/2010 X1 (Elenin)) is a long-period comet.
600,000,000,000,000,000,000,000,000,000
The orbital period of Halley's Comet is about 75.3 years.
each 76 years
Halley's comet is in orbit round the sun. Its orbit time is about 75 years, but as the orbital path is long and narrow, most of that is spent far out where we cannot see it. We see it for a few months when it is near the sun.