11P/Tempel-Swift-LINEAR (0011P)


Type: Periodic Perihelion date: 26 November 2020 Perihelion distance (q): 1.4 Aphelion distance (Q) : 5.2 Period (years): 5.9 Eccentricity (e): 0.58 Inclination (i): 14.4 JPL orbit diagram COBS lightcurve 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