11P/Tempel–Swift–LINEAR

For other comets of the same name, see Comet Tempel, Comet Swift, and List of comets discovered by the LINEAR project.

11P/Tempel–Swift–LINEAR is a periodic comet with a 5.95-year orbit around the Sun.

11P/Tempel–Swift–LINEAR

Infrared image of Comet T–S–L taken by NEOWISE on 4 January 2021.
Discovery[1]
Discovered by	Ernst Tempel Lewis Swift LINEAR
Discovery date	27 November 1869 11 October 1880 7 December 2001
Designations
MPC designation	P/1869 W1, P/1880 T1 P/2001 X3
Alternative designations	1869 III, 1880 IV 1891 V, 1908 II 1869c, 1880e, 1891d 1908d
Orbital characteristics[2][3]
Epoch	17 October 2024 (JD 2460600.5)
Observation arc	154.75 years
Number of observations	1,337
Aphelion	5.18 AU
Perihelion	1.388 AU
Semi-major axis	3.284 AU
Eccentricity	0.57756
Orbital period	5.95 years
Inclination	14.435°
Longitude of ascending node	238.87°
Argument of periapsis	168.04°
Mean anomaly	235.14°
Last perihelion	26 November 2020[3]
Next perihelion	9 November 2026[4]
TJupiter	2.839
Earth MOID	0.403 AU
Jupiter MOID	0.326 AU
Comet total magnitude (M1)	15.2
Comet nuclear magnitude (M2)	18.6

Observational history

Discovery

In 1869, the comet's perihelion was around 1.063 AU (159.0 million km) from the Sun.^[5] Ernst Wilhelm Leberecht Tempel originally discovered the comet on 27 November 1869, from his observatory at Marseille. It was later observed by Lewis Swift from the Warner Observatory on 11 October 1880, and he realised that it is the same comet as Tempel's.^[6]

Loss and recovery

After 1908, the comet became an unobservable lost comet due to a series of four close flybys of Jupiter between 1911 and 1946^[a] perturbing its orbit significantly enough that made subsequent apparitions of the comet unfavorable for observations in decades.^[7] Nevertheless, Brian G. Marsden computed the resulting orbit based on the observations between 1891 and 1908, and predicted a favorable return in 1963, however the comet remained unobserved.^[7] Despite this, additional predictions of the comet's favorable returns were later attempted by Marsden and Zdenek Sekanina in 1971,^[8] and Shuichi Nakano in 1995.

On 7 December 2001, an object designated as P/2001 X3 was found by the Lincoln Near-Earth Asteroid Research (LINEAR) program.^[9] Analysis of images taken between 10 September and 17 October 2001 later confirmed that P/2001 X3 is the recovery of the previously lost comet Tempel–Swift.^[1]

Recent observations

The comet was not observed during the 2008 unfavorable apparition^[10][3] 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.^[3] The comet will next come to perihelion on 9 November 2026,^[4] then two days later on the 11th, make a closest approach to Earth of 0.4012 AU (60.02 million km).^[2]

Notes

1. 11P/Tempel–Swift–LINEAR approached Jupiter at a distance of 0.61 AU (May 1911), 0.50 AU (July 1923), 0.56 AU (April 1935), and 1.33 AU (November 1946) respectively.^[7][8]