8P/Tuttle
A Jupiter-family comet that spawns the Ursid meteor shower.
8P/Tuttle, also called Tuttle's Comet or Comet Tuttle, is a periodic comet that orbits the Sun once every 13.6 years. By the older standard, it qualifies as a Jupiter-family comet because its orbital period is under 20 years, but it does not meet the modern criterion of having a Tisserand parameter with Jupiter between 2 and 3. This comet produces the Ursid meteor shower, which peaks in late December.
Its most recent perihelion occurred on August 27, 2021, when it shone at roughly apparent magnitude 9 and had a solar elongation of 26 degrees. About two weeks later, on September 12, 2021, it reached a distance of roughly 1.8 AU (270 million km) from Earth—nearly as far as it can get from our planet while near perihelion.
During its 2008 return, the comet was visible to the naked eye under dark skies. On December 30, 2007, it passed very close to the Triangulum Galaxy in the sky. On January 1, 2008, it came within 0.25282 AU (about 37.8 million km) of Earth. Throughout February 2008, it could be seen telescopically from the Southern Hemisphere in the constellation Eridanus. Predictions that the 2007 Ursid meteor shower might be unusually strong because of the comet’s return did not come true; meteor counts remained within normal levels.
Radar observations from the Arecibo Observatory in January 2008 revealed that the comet’s nucleus is a contact binary. Its diameter is estimated at 4.5 km (2.8 mi), based on the equivalent diameter of a sphere whose volume equals that of two components—one roughly 3 km by 4 km (1.9 mi by 2.5 mi).
In 2019, 8P/Tuttle was listed as one of ten backup targets for the European Space Agency’s Comet Interceptor mission. That spacecraft is scheduled to launch in 2029, and if 8P is selected as the target, it would perform a flyby on March 26, 2035.
Quick Facts
- Discoverer
- Horace Parnell Tuttle
- Discovery Date
- January 5, 1858
- Mpc Name
- P/1790 A2, P/1858 A1 / P/1871 T1
- Designations
- 1790 II, 1858 I, 1871 III · 1885 IV, 1899 III · 1912 IV, 1926 IV · 1939 X, 1967 V · 1980 XIII, 1994 XV
- Orbit Ref
- MPC · jpl1
- Observation Arc
- 232.14 years
- Earliest Precovery Date
- January 28, 1790Denning_1916
- Obs
- 316
- Epoch
- January 21, 2022 (JD 2459600.5)
- Semimajor
- 5.707 AU
- Perihelion
- 1.026 AU
- Aphelion
- 10.39 AU
Facts from the source article.
Lore & Background
During its 2008 perihelion, the comet was a naked-eye object under dark skies. On December 30, 2007, it was in close conjunction with the Triangulum Galaxy. On January 1, 2008, it passed Earth at a distance of 0.25282 AU (37.821 million km). It was visible telescopically to Southern Hemisphere observers in the constellation Eridanus throughout February 2008. Predictions that the 2007 Ursid meteor shower could have possibly been stronger than usual due to the return of the comet did not appear to materialize, as counts were in the range of normal distribution.
Radar observations of Comet Tuttle in January 2008 by the Arecibo Observatory show it to be a contact binary. The comet nucleus is estimated at 4.5 km (2.8 mi) in diameter, using the equivalent diameter of a sphere having a volume equal to the sum of a 3 km × 4 km sphere.
In 2019, 8P/Tuttle was listed as one of 10 backup targets of the European Space Agency's Comet Interceptor mission. Scheduled for launch in 2029, the spacecraft may conduct a flyby of 8P on March 26, 2035 if selected.
Reader's Guide
8P/Tuttle is notable as the parent body of the Ursid meteor shower, which peaks in late December each year. Its 2008 apparition provided a rare naked-eye view under dark skies and a close conjunction with the Triangulum Galaxy. Radar observations at Arecibo revealed its contact-binary nucleus, a structure that informs understanding of comet formation and evolution. The comet's orbital characteristics place it at the boundary of Jupiter-family comet definitions, highlighting the complexity of classifying such objects. Its selection as a backup target for the Comet Interceptor mission underscores its continued scientific interest, with a potential flyby in 2035 that could yield further data on its composition and structure. The comet's 2021 perihelion, though distant from Earth, allowed continued monitoring of its activity.
Did You Know?
- 8P/Tuttle is responsible for the Ursid meteor shower in late December.
- Radar observations in January 2008 by Arecibo Observatory show the comet nucleus is a contact binary.
More in Named Comets, Part 5 1-24
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