Periodic comets (also known as short-period comets) are comets having orbital periods of less than 200 years or that have been observed during more than a single perihelion passage[1] (e.g. 153P/IkeyaZhang). "Periodic comet" is also sometimes used to mean any comet with a periodic orbit, even if greater than 200 years.
Periodic comets receive a permanent number prefix usually after the second perihelion passage, which is why there are a number of unnumbered periodic comets, such as P/2005 T5 (Broughton). Comets that are not observed after a number of perihelion passages, or presumed to be destroyed, are given the D designation, and likewise comets given a periodic number and subsequently lost are given [n]D instead of [n]P, such as 3D/Biela or 5D/Brorsen.
In nearly all cases, comets are named after their discoverer(s), but in a few cases such as 2P/Encke and 27P/Crommelin they were named for a person who calculated their orbits (the orbit computers). The long-term orbits of comets are difficult to calculate because of errors in the known trajectory that accumulate with perturbations from the planets, and in the days before electronic computers some people dedicated their entire careers to this. Even so, quite a few comets were lost because their orbits are also affected by non-gravitational effects such as the release of gas and other material that forms the comet's coma and tail. Unlike a long-period comet, the next perihelion passage of a numbered periodic comet can be predicted with a high degree of accuracy.
Periodic comets sometimes bear the same name repeatedly (e.g. the nine ShoemakerLevy comets or the twenty-four NEAT comets); the IAU system distinguishes between them either through the number prefix or by the full designation (e. g. 181P and 192P are both "Comet ShoemakerLevy"). In the literature, an informal numbering system is applied to periodic comets (skipping the non-periodic ones), thus 181P and 192P are known as Comet ShoemakerLevy 6 and Comet ShoemakerLevy 1, respectively. Non-periodic ShoemakerLevy comets are interleaved in this sequence: C/1991 B1 between 2 and 3, C/1991 T2 between 5 and 6, C/1993 K1 and C/1994 E2 after ShoemakerLevy 9.
In comet nomenclature, the letter before the "/" is either "C" (a non-periodic comet), "P" (a periodic comet), "D" (a comet that has been lost or has disintegrated), "X" (a comet for which no reliable orbit could be calculated usually historical comets), or "A" for an object that was mistakenly identified as a comet, but is actually a minor planet.[1]
Some lists retain the "C" prefix for comets of periods larger than about 30 years until their return is confirmed.[2]
For a list of numbered periodic comets, see List of numbered comets.
While Jupiter-family comets are officially defined by (2< TJupiter <3), they can also be loosely defined by any comet with a period of less than 20 years, a relatively low inclination, and an orbit coinciding loosely with that of Jupiter's. These comets are often patchily observed, as orbital interactions with the planet often cause comets' orbits to become perturbed, causing them to not be found at the expected position in the sky and subsequently lost. Additionally, their low cometary albedos and frequent proximity to the Sun compared to Oort Cloud comets cause them to much more quickly become depleted of volatiles, making them comparatively dimmer than comets with longer orbital periods.
Read more here:
List of periodic comets - Wikipedia, the free encyclopedia
- Comet - Wikipedia, the free encyclopedia - November 21st, 2013 [November 21st, 2013]
- Comets - The Nine Planets - November 21st, 2013 [November 21st, 2013]
- Comets - Astronomy For Kids - KidsAstronomy.com - November 21st, 2013 [November 21st, 2013]
- Views of the Solar System: Comets - November 21st, 2013 [November 21st, 2013]
- Comets (extra footage) - Video - November 21st, 2013 [November 21st, 2013]
- Solar flare update. 6 comets! Nov 28th ISON perihelion! - Video - November 21st, 2013 [November 21st, 2013]
- Comets game 2end goal - Video - November 21st, 2013 [November 21st, 2013]
- Missouri Comets vs. Milwaukee Wave - Video - November 21st, 2013 [November 21st, 2013]
- Football: Comets Advance Past Momence - Video - November 21st, 2013 [November 21st, 2013]
- Caliber Cheer Comets Nov 9 2013 - Video - November 21st, 2013 [November 21st, 2013]
- Two Comets Are About to Fly By Mercury | NASA Space Science HD Video - Video - November 21st, 2013 [November 21st, 2013]
- Comets win on tiebreaker - December 20th, 2013 [December 20th, 2013]
- Comets fend off Wildcat attack - December 20th, 2013 [December 20th, 2013]
- Free throws bring Comets down - December 20th, 2013 [December 20th, 2013]
- Comets continue solid play on their home ice - December 20th, 2013 [December 20th, 2013]
- Comets Beat Heat 4-2 - December 20th, 2013 [December 20th, 2013]
- Comets in the Community - December 20th, 2013 [December 20th, 2013]
- Comets pick up third straight win over Heat - December 20th, 2013 [December 20th, 2013]
- Comets Welcome Back Old Rival - December 20th, 2013 [December 20th, 2013]
- Comets Cool Abbotsford 4-2 - December 20th, 2013 [December 20th, 2013]
- Comets – Facts and Information about Comets | Space.com - December 20th, 2013 [December 20th, 2013]
- Comets v Wave 121313 Highlights - Video - December 20th, 2013 [December 20th, 2013]
- Highlights - Comets vs. Monsters 12/15/13 - Video - December 20th, 2013 [December 20th, 2013]
- Weekly Space Hangout - Preventing Asteroids, More Comets, Worldview Balloon - Video - December 20th, 2013 [December 20th, 2013]
- Pens 1 - Comets 0 - Video - December 20th, 2013 [December 20th, 2013]
- Milwaukee Waves Cheap Shot Vs. Missouri Comets - 12.13.13 - Video - December 20th, 2013 [December 20th, 2013]
- Hometown Nights - Tarso Miller and the Wild Comets - Video - December 20th, 2013 [December 20th, 2013]
- Hangout with Comets Nova and Deathlyhall - Video - December 20th, 2013 [December 20th, 2013]
- Comets vs St. Louis Ambush - Video - December 20th, 2013 [December 20th, 2013]
- Shake, Rattle and Roll Bill Haley and His Comets - Sheet Music - Easy Alto Sax Version - Video - December 20th, 2013 [December 20th, 2013]
- Comets Shut Out Heat 3-0 - December 21st, 2013 [December 21st, 2013]
- Administration - December 21st, 2013 [December 21st, 2013]
- Bill Haley And His Comets ' R-O-C-K' 78 rpm - Video - December 21st, 2013 [December 21st, 2013]
- Bill Haley And His Comets ' The Saints Rock 'N Roll' 78 rpm - Video - December 21st, 2013 [December 21st, 2013]
- Nicklas Jensen's Shootout Winning Deke 12-15-13 - Video - December 21st, 2013 [December 21st, 2013]
- Missouri Comets Night with Miles - 12.13.13 - Video - December 21st, 2013 [December 21st, 2013]
- 12/13/13 Comets 5 vs. Senators 2 - Video - December 21st, 2013 [December 21st, 2013]
- Comets rock Bulldogs for first win - December 22nd, 2013 [December 22nd, 2013]
- Comets Deposit Life's Building Blocks Across the Cosmos!(Dr.Ruehl) - Video - December 22nd, 2013 [December 22nd, 2013]
- Comets beat AHL rival Abbotsford again with shutout - December 23rd, 2013 [December 23rd, 2013]
- Comets Win Streak Grows to Four Games - December 23rd, 2013 [December 23rd, 2013]
- Comets Corner: On the Mask - December 23rd, 2013 [December 23rd, 2013]
- 'Comets of the Centuries': 500 Years of the Greatest Comets Ever Seen - December 23rd, 2013 [December 23rd, 2013]
- Hackensack High School (NJ) Football Home - MaxPreps.com - December 23rd, 2013 [December 23rd, 2013]
- Little Comets - Isles (Music Video) - Video - December 23rd, 2013 [December 23rd, 2013]
- Comets Have Two Players on MISL Team of Week - December 25th, 2013 [December 25th, 2013]
- ONE FOR THE RECORD DECEMBER 20 2013 21 FUKUSHIMA COMETS EARTHQUAKES NMR GZ PAUL AND BP - Video - December 25th, 2013 [December 25th, 2013]
- Comets in the Community: Christmas at St. Luke's - December 26th, 2013 [December 26th, 2013]
- Best comets of last 500 years - December 26th, 2013 [December 26th, 2013]
- STRANGE EVENTS In 2013 Earthquakes, Mass Animal Deaths, Extreme Weather, OORT Cloud Comets - Video - December 26th, 2013 [December 26th, 2013]
- Utica Comets " 'Twas the Night" - Video - December 26th, 2013 [December 26th, 2013]
- Missouri Comets vs. Rochester Lancers - Video - December 26th, 2013 [December 26th, 2013]
- Chasing Comets: In search of secrets about our origins - Video - December 26th, 2013 [December 26th, 2013]
- DREAM X2 COMETS/STARS FLYING OVERHEAD, MASSIVE SONIC BOOMS EARTH HIT POSSIBLY. - Video - December 26th, 2013 [December 26th, 2013]
- What are comets? - Video - December 26th, 2013 [December 26th, 2013]
- Game Preview: Syracuse Silver Knights at Missouri Comets and St. Louis Ambush - December 27th, 2013 [December 27th, 2013]
- Clark's performance boosts Clayton over Moss Point - December 27th, 2013 [December 27th, 2013]
- Gameday: Comets vs. Binghamton - December 27th, 2013 [December 27th, 2013]
- Comets Battle for First Place - December 27th, 2013 [December 27th, 2013]
- Gameday: Comets vs. Hamilton - December 28th, 2013 [December 28th, 2013]
- Comets fall to Senators - December 28th, 2013 [December 28th, 2013]
- Comets end winning streak - December 28th, 2013 [December 28th, 2013]
- Comets vs Syracuse Silver Knights - Video - December 28th, 2013 [December 28th, 2013]
- Winning Comets Soccer - Video - December 28th, 2013 [December 28th, 2013]
- Comets Lose in Final Minutes - December 29th, 2013 [December 29th, 2013]
- CometsTV: 12-27-13 Utica Comets vs. Binghamton Senators Highlights - Video - December 29th, 2013 [December 29th, 2013]
- Comets knock off Aquin for second time this season - December 31st, 2013 [December 31st, 2013]
- Comets fall after late rally - December 31st, 2013 [December 31st, 2013]
- CometsTV: 12-28-13 Utica Comets vs. Hamilton Bulldogs Highlights - Video - December 31st, 2013 [December 31st, 2013]
- Comets Corner: Kellan Lain - January 1st, 2014 [January 1st, 2014]
- Comets Welcome New Year - January 1st, 2014 [January 1st, 2014]
- Comets Media Game 2013 - Video - January 1st, 2014 [January 1st, 2014]
- 1957 AMI H200 playing Bill Haley and his Comets Rock Around The Clock. - Video - January 1st, 2014 [January 1st, 2014]
- 7 Amazing Christmas Kinder Surprise Eggs SMURFS cars, comets Unwrapping Review Chocolate Easter Toys - Video - January 1st, 2014 [January 1st, 2014]
- Shootout - Dogs @ Comets - 12/2813 - END - Video - January 1st, 2014 [January 1st, 2014]
- Shootout - Dogs @ Comets - 12/2813 - Video - January 1st, 2014 [January 1st, 2014]
- Catonsville girls basketball shows promise for another strong season - January 2nd, 2014 [January 2nd, 2014]
- Gameday: Comets vs. Lake Erie - January 2nd, 2014 [January 2nd, 2014]
- Comets Kick off New Year with Exciting Win - January 2nd, 2014 [January 2nd, 2014]
- Comets Remain Hot at Home with 3-2 Decision over Lake Erie - January 2nd, 2014 [January 2nd, 2014]