162P/Siding Spring

For other comets discovered by the Siding Spring Observatory, see Comet Siding Spring.

162P/Siding Spring

The comet on 12 November 2004, displaying a narrow tail
Discovery [1]
Discovery site	Siding Spring Observatory
Discovery date	10 October 2004
Designations
Alternative 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°
Longitude of ascending node	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]
Sidereal rotation period	32.864±0.001 hours [5]
Geometric albedo	0.022±0.003 [5]
Spectral type	(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]

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

References

1. 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. "162P/Siding Spring – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory . Retrieved 20 July 2023.
3. "162P/Siding Spring Orbit". Minor Planet Center . Retrieved 25 July 2025.
4. 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.
5. 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 .
6. M. M. Knight; R. Kokotanekova; N. H. Samarasinha (2023). "Physical and Surface Properties of Comet Nuclei from Remote Observations". arXiv: 2304.09309 [astro-ph.EP].
7. 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.
8. 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 .
9. 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.

External links

• 162P/Siding Spring at the JPL Small-Body Database
  • Close approach  · Discovery  · Ephemeris  · Orbit viewer  · Orbit parameters  · Physical parameters
• Cometary activity found on asteroidal object 2004 TU12 - La Cañada Observatory report

Numbered comets
Previous 161P/Hartley–IRAS	162P/Siding Spring	Next 163P/NEAT