| 8P/Tuttle | |
| Discoverer: | Horace Parnell Tuttle |
| Discovery Date: | January 5, 1858 |
| Designations: | 1790 II; 1858 I; 1871 III; 1885 IV; 1899 III; 1912 IV; 1926 IV; 1939 X; 1967 V; 1980 XIII; 1994 XV |
| Epoch: | 2022-01-21 |
| Semimajor: | 5.707 AU |
| Perihelion: | 1.026 AU |
| Aphelion: | 10.39 AU |
| Eccentricity: | 0.8202 |
| Period: | 13.6 yr |
| Inclination: | 54.911° |
| Earth Moid: | 0.095AU |
| Last P: | August 27, 2021[1] January 27, 2008 |
| Next P: | 2035-Apr-18 |
| Dimensions: | 4.5 km contact binary |
8P/Tuttle (also known as Tuttle's Comet or Comet Tuttle) is a periodic comet with a 13.6-year orbit. It fits the classical definition of a Jupiter-family comet with an orbital period of less than 20 years, but does not fit the modern definition of (2 < TJupiter< 3). Its last perihelion passage was 27 August 2021 when it had a solar elongation of 26 degrees at approximately apparent magnitude 9. Two weeks later, on September 12, 2021, it was about 1.8abbr=unitNaNabbr=unit from Earth which is about as far from Earth as the comet can get when the comet is near perihelion.
Comet 8P/Tuttle is responsible for the Ursid meteor shower in late December.[2]
Under dark skies, the comet was a naked-eye object. Perihelion was late January 2008 and, as of February, was visible telescopically to Southern Hemisphere observers in the constellation Eridanus. On December 30, 2007, it was in close conjunction with spiral galaxy M33. On January 1, 2008, it passed Earth at a distance of 0.25282abbr=onNaNabbr=on.
Predictions that the 2007 Ursid meteor shower could have possibly been stronger than usual due to the return of the comet,[3] 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.[4] [5] The comet nucleus is estimated at 4.5 km in diameter, using the equivalent diameter of a sphere having a volume equal to the sum of a 3 km and 4 km sphere.[6]