![]() The comet on 12 November 2004, displaying a narrow tail | |
Discovery [1] | |
---|---|
Discovery site | Siding Spring Observatory |
Discovery date | 10 October 2004 |
Designations | |
P/2004 TU12 | |
Orbital characteristics [2] [3] | |
Epoch | 5 May 2025 (JD 2460800.5) |
Observation arc | 35.27 years |
Earliest precovery date | 23 March 1990 |
Number of observations | 3,273 |
Aphelion | 4.894 AU |
Perihelion | 1.289 AU |
Semi-major axis | 3.092 AU |
Eccentricity | 0.58295 |
Orbital period | 5.33 years |
Inclination | 27.554° |
30.878° | |
Argument of periapsis | 357.24° |
Mean anomaly | 291.51° |
Last perihelion | 7 December 2020 |
Next perihelion | 17 May 2026 |
TJupiter | 2.792 |
Earth MOID | 0.239 AU |
Jupiter MOID | 0.587 AU |
Physical characteristics | |
Mean diameter | 14.06±0.96 km [4] |
32.864±0.001 hours [5] | |
0.022±0.003 [5] | |
(V–R) = 0.45±0.01 [6] | |
Comet total magnitude (M1) | 15.2 |
162P/Siding Spring is a Jupiter-family comet with an orbital period of 5.3 years. It was discovered in images obtained on 10 October 2004 as part of the Siding Spring Survey. [1]
The comet was discovered during the Siding Spring Survey as an asteroidal object shining with an apparent magnitude of 14.1 but a tail extending for about 4 arcminutes was observed on 12 November 2004, indicating that it is a comet. [1] The tail grew longer the next days, reaching a length of over 10 arcminutes on 15 November. Two days later the tail was fainter, and barely visible within one arcminute from the nucleus. [7] On 21 October 2031, the comet will approach Earth at a distance of 0.2456 AU (36.74 million km). [2]
The comet was observed by NASA Infrared Telescope Facility in 2004, finding that the nucleus has an effective radius of 6.0±0.8 km, which corresponds to a visual albedo of 0.034±0.014, [8] and a reflectance spectrum typical of a D-type asteroid. [9] Further observations by the Spitzer Space Telescope indicate an effective radius of 7.03 ± 0.48 km. [4] This is one of the largest nuclei of Jupiter family comets with known radius. [8] More detailed observations indicate that the nucleus has axis ratios a/b = 1.56 and b/c = 2.33, and could possibly have two lobes. [5] The sidereal period of the comet is 32.864±0.001 hours. [5]