11P/Tempel-Swift-LINEAR (0011P)
TRY AGAIN 2026
Type: Periodic
Perihelion date: 9 November 2026
Perihelion distance (q): 1.4
Aphelion distance (Q) : 5.2
Period (years): 6.0
Eccentricity (e): 0.58
Inclination (i): 14.4
JPL orbit diagram
COBS lightcurve
Atlas
Ernst Wilhelm Liebrecht Tempel (Marseilles, France) discovered this comet on 27
November 1869 in Pegasus. Shortly thereafter, observers were describing it as
diffuse and circular, with a coma about 5 arc minutes across. The comet was only
observed for 39 days and although recognised as a short-period comet, astronomers
were uncertain as to the exact period.
An attempt to find the comet in 1875 was unsuccessful.
Lewis Swift (Warner Observatory, New York) discovered a diffuse, circular comet in
Pegasus on 11 October 1880. By mid-November, astronomers realized Swift's comet
was a return of Tempel's 1869 comet. The final observation of the 1880-1 apparition
determined that the comet's orbital period was 5.5 years, making every other return
favorable and the others unfavorable.
It was recovered in 1891 and 1908, but perturbations by Jupiter caused the comet to
become unobservable after 1908 and the comet was listed as lost.
On 7 December 2001, astronomers at MIT's Lincoln Laboratory in New Mexico found
an object on images obtained in the course of the Lincoln Near Earth Asteroid
Research (LINEAR) program. They were using a 1.0-m reflector and a CCD camera.
Prediscovery images were subsequently found on additional LINEAR images from 10
September and 17 October. LINEAR images on 17 December revealed the object
was diffuse, and this was confirmed on 19 December by G. Hug (Eskridge, Kansas).
An orbit by B. G. Marsden (Central Bureau for Astronomical Telegrams) then
revealed this was a short-period comet with a period of 6.37 years. C. Hergenrother
(Lunar and Planetary Laboratory) and K. Muraoka (Kochi, Japan) independently
suggested to Marsden that the LINEAR comet might be a return of comet Tempel-
Swift. The link was almost immediately confirmed by Marsden and S. Nakano
(Sumoto, Japan).
Observations (VEMag = visual equivalent magnitude)
Date
10x10 mag
Error
VEmag
Coma '
09-Oct-20
17.50
0.07
17.0
0.4
06-Nov-20
16.74
0.04
15.0
0.9
13-Nov-20
16.56
0.04
14.4
1.5
20-Nov-20
16.61
0.07
14.5
1.3
06-Dec-20
16.80
0.08
14.1
1.3
14-Dec-20
16.94
0.05
14.9
1.1
10-Jan-21
16.7
0.4
31-Jan-21
17.7
0.4
09-Feb-21
18.3
0.4