162P/Siding Spring
Periodic comet
From Wikipedia, the free encyclopedia
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 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 |
Observational history
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]
Physical characteristics
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]
See also
- 107P/Wilson-Harrington and 133P/Elst-Pizarro - comets with similar intermittent activity