| 11P/Tempel–Swift–LINEAR | |
| Discoverer: | Ernst Tempel, Lewis Swift &<br />LINEAR |
| Discovery Date: | November 27, 1869 |
| Designations: | 1869 W1; 1869 III; 1869c; 1880 T1; 1880 IV; 1880e; 1891 V; 1891d; 1908 II; 1908d; 2001 X3 |
| Epoch: | 2023-02-25 |
| Semimajor: | 3.284 AU |
| Perihelion: | 1.388 AU |
| Aphelion: | 5.18 AU |
| Eccentricity: | 0.5775 |
| Period: | 5.95 yr |
| Inclination: | 14.429° |
| Asc Node: | 238.87° |
| Arg Peri: | 167.99° |
| Last P: | November 26, 2020 August 26, 2014 May 4, 2008 (unobserved) |
| Next P: | November 9, 2026 |
11P/Tempel–Swift–LINEAR is a periodic Jupiter-family comet in the Solar System.
In 1869 perihelion (closest approach to the Sun) was 1.063 AU. Ernst Wilhelm Leberecht Tempel (Marseille) originally discovered the comet on November 27, 1869, it was later observed by Lewis Swift (Warner Observatory) on October 11, 1880, and realised to be the same comet.
After 1908 the comet became an unobservable lost comet, but on December 7, 2001, an object was found by the Lincoln Near-Earth Asteroid Research (LINEAR) program, and confirmed by previous images from September 10 and October 17 as being the same comet. The comet was not observed during the 2008 unfavorable apparition because the perihelion passage occurred when the comet was on the far side of the Sun. The comet was observed during the 2014 and 2020 apparitions.
The comet will next come to perihelion on 9 November 2026, then two days later on the 11th, make a closest approach to Earth of 0.4012abbr=unitNaNabbr=unit.