162P/Siding Spring

162P/Siding Spring
The comet on 12 November 2004, displaying a narrow tail
Discovery
Discovery siteSiding Spring Observatory
Discovery date10 October 2004
Designations
P/2004 TU12
Siding Spring 2
Orbital characteristics
Epoch5 May 2025 (JD 2460800.5)
Observation arc36.48 years
Earliest precovery date23 March 1990
Number of
observations		3,317
Aphelion4.894 AU
Perihelion1.289 AU
Semi-major axis3.092 AU
Eccentricity0.58295
Orbital period5.33 years
Inclination27.554°
30.878°
Argument of
periapsis		357.24°
Mean anomaly291.51°
Last perihelion17 May 2026
Next perihelion14 October 2031
TJupiter2.792
Earth MOID0.239 AU
Jupiter MOID0.587 AU
Physical characteristics
Mean diameter
14.06±0.96 km
32.864±0.001 hours
0.022±0.003
(V–R) = 0.45±0.01
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.

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. 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. On 21 October 2031, the comet will approach Earth at a distance of 0.2456 AU (36.74 million km).

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, and a reflectance spectrum typical of a D-type asteroid. Further observations by the Spitzer Space Telescope indicate an effective radius of 7.03 ± 0.48 km. This is one of the largest nuclei of Jupiter family comets with known radius. 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. The sidereal period of the comet is 32.864±0.001 hours.

See also

Notes

  1. ↑ Observation arc from the Minor Planet Center database covering dates from 23 March 1990 until 14 September 2026.

References

  1. 1 2 3 F. Mallia; G. Masi; R. Wilcox; J. Lacruz (1 November 2004). D. W. Green (ed.). "Comet P/2004 TU12 (Siding Spring)". IAU Circular. 8436 (1). Bibcode:2004IAUC.8436....1M. ISSN 0081-0304.
  2. ↑ "Periodic Comet Names and Designations". Planetary Data System: Small Body Node. NASA. Retrieved 25 September 2026.
  3. 1 2 "162P/Siding Spring – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 20 July 2023.
  4. ↑ "162P/Siding Spring Orbit". Minor Planet Center. Retrieved 25 July 2025.
  5. ↑ S. R. Chesley; M. S. Keesey (20 December 2005). Comet Apparitions: 2005–2040 (PDF) (Report). Jet Propulsion Laboratory. Retrieved 27 September 2026.
  6. 1 2 Y. R. Fernández; M. S. P. Kelley; P. L. Lamy; I. Toth; O. Groussin; et al. (2013). "Thermal properties, sizes, and size distribution of Jupiter-family cometary nuclei". Icarus. 226 (1): 1138–1170. arXiv:1307.6191. Bibcode:2013Icar..226.1138F. doi:10.1016/j.icarus.2013.07.021.
  7. 1 2 3 4 A. Donaldson; R. Kokotanekova; A. Rożek; C. Snodgrass; et al. (2023). "Characterizing the nucleus of comet 162P/Siding Spring using ground-based photometry". Monthly Notices of the Royal Astronomical Society. 521 (1): 1518–1531. arXiv:2302.12141. doi:10.1093/mnras/stad616.
  8. ↑ M. M. Knight; R. Kokotanekova; N. H. Samarasinha (2024). "Physical and Surface Properties of Comet Nuclei from Remote Observations". In K. J. Meech (ed.). Comets III. University of Arizona Press. pp. 361–404. arXiv:2304.09309. JSTOR jj.21819446.18.
  9. ↑ G. Masi (1 November 2004). D. W. Green (ed.). "Comet P/2004 TU12 (Siding Spring)". IAU Circular. 8439 (1). Bibcode:2004IAUC.8439....1M. ISSN 0081-0304.
  10. 1 2 Y. R. Fernández; H. Campins; M. Kassis; C. W. Hergenrother; et al. (2006). "Comet 162P/Siding Spring: A Surprisingly Large Nucleus". The Astronomical Journal. 132 (3): 1354–1360. arXiv:astro-ph/0608387. Bibcode:2006AJ....132.1354F. doi:10.1086/506252.
  11. ↑ H. Campins; J. Ziffer; J. Licandro; N. Pinilla-Alonso; et al. (2006). "Nuclear Spectra of Comet 162P/Siding Spring (2004 TU12)". The Astronomical Journal. 132 (3): 1346–1353. Bibcode:2006AJ....132.1346C. doi:10.1086/506253.