112P/Urata–Niijima

112P/Urata–Niijima
Comet Urata–Niijima imaged from the Zwicky Transient Facility on 27 January 2020
Discovery[1]
Discovered byTakeshi Urata
Tsuneo Niijima
Discovery siteOjima, Japan
Discovery date30 October 1986
Designations
  • P/1986 UD, P/1986 WP5
  • P/1986 TD4, P/1993 U1[2]
  • 1986 XVI, 1993 XII
  • 1986o, 1993q[2]
Orbital characteristics[3][4]
Epoch9 June 2026 (JD 2461200.5)
Observation arc39.88 years[a]
Earliest precovery date4 October 1986
Number of
observations		653
Aphelion5.601 AU
Perihelion1.441 AU
Semi-major axis3.521 AU
Eccentricity0.59071
Orbital period6.61 years
Inclination24.204°
31.794°
Argument of
periapsis		21.585°
Mean anomaly344.36°
Last perihelion7 February 2020
Next perihelion21 September 2026[5]
TJupiter2.688
Earth MOID0.481 AU
Jupiter MOID0.316 AU
Physical characteristics[6]
Mean radius
0.90±0.05 km
0.04
(V–R) = 0.53±0.04[7]
Comet total
magnitude (M1)		13.4
Comet nuclear
magnitude (M2)		17.9

Comet Urata–Niijima, also known as 112P/Urata–Niijima, is a Jupiter-family comet with a 6.6-year orbit around the Sun. It was the only comet discovered by Japanese astronomers Takeshi Urata and Tsuneo Niijima.

Observational history

1986 apparition

The comet was first spotted by Urata and Niijima as a fast-moving asteroid-like object called 1986 UD, on 30 October 1986.[1] At the time, it was a 16th-magnitude object within the constellation Aries.[b] Four days later, Tsutomu Seki would confirm the object's cometary nature after spotting a very faint, diffuse coma on 3 November 1986.[9] Further observations by Miklós Lovas and orbital calculations by Brian G. Marsden determined the periodic nature of Urata–Niijima on 17 November 1986.[10] Its brightness remained consistent at roughly 15–16 throughout the entire apparition.[11] The comet was last observed by Tom Gehrels on 27 March 1987.[8]

On August 1987, Shuichi Nakano would later link two asteroids, 1986 TD4 and 1986 WP5, as the same object as Comet Urata–Niijima.[8]

Subsequent apparitions

The comet was recovered by James V. Scotti at the Kitt Peak Observatory on 20 October 1993.[12] As with the previous apparition in 1986, the comet never went brighter than apparent magnitude 15, and it was an extremely faint 22nd-magnitude object when it was last seen in April 1994.[13] Philippe L. Lamy and Harold A. Weaver used the Hubble Space Telescope to recover the comet on its next apparition on 4 March 2000.[14]

At the perihelion passage in late September 2026 the solar elongation will be 83 degrees with a declination of +34. The comet should brighten to about magnitude 15.5 placing it near the limit of smart telescopes.

Physical characteristics

The nucleus of the comet has an effective radius of 0.90 ± 0.05 km (0.559 ± 0.031 mi), assuming a geometric albedo of 0.04.[6] During its 1983 apparition, emissions of CN, C3 and C2 were detected from Urata–Niijima's coma.[15]

Notes

  1. ↑ Observation arc from the Minor Planet Center database covering dates from 4 October 1986 until 22 August 2026.
  2. ↑ Reported initial position upon discovery was: α = 2h 03.2m , δ = 19° 07′[8]

References

  1. 1 2 T. Urata; T. Niijima (3 November 1986). B. G. Marsden (ed.). "1986 UD". IAU Circular. 4267 (2). Bibcode:1986IAUC.4267....2U.
  2. 1 2 "Comet Names and Designations". International Comet Quarterly. Retrieved 29 August 2026.
  3. ↑ "112P/Urata–Niijima – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 21 November 2023.
  4. ↑ "112P/Urata–Niijima Orbit". Minor Planet Center. Retrieved 17 June 2014.
  5. ↑ "Horizons Batch for 112P/Urata–Niijima (90000986) on 2026-Sep-21" (Perihelion occurs when rdot flips from negative to positive). JPL Horizons. Retrieved 6 July 2023. (JPL#35 Soln.date: 2021-Sep-20)
  6. 1 2 P. L. Lamy; I. Toth; H. A. Weaver; M. F. A'Hearn; L. Jorda (2009). "Properties of the nuclei and comae of 13 ecliptic comets from Hubble Space Telescope snapshot observations" (PDF). Astronomy & Astrophysics. 508 (2): 1045–1056. Bibcode:2009A&A...508.1045L. doi:10.1051/0004-6361/200811462. S2CID 125249770.
  7. ↑ 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.
  8. 1 2 3 Kronk, Meyer & Seargent 2017, pp. 234–237.
  9. ↑ T. Seki; T. Urata; T. Niijima; K. Suzuki (5 November 1986). B. G. Marsden (ed.). "Comet Urata–Niijima (1986o)". IAU Circular. 4269 (1). Bibcode:1986IAUC.4269....1S.
  10. ↑ M. Lovas (17 November 1986). B. G. Marsden (ed.). "Periodic Comet Urata–Niijima (1986o)". IAU Circular. 4270 (1). Bibcode:1986IAUC.4270....1L.
  11. ↑ M. J. Hendrie (1987). "Comet Section: Urata–Niijima 1986o (1986 UD)". Journal of the British Astronomical Association. 97 (2): 67. Bibcode:1987JBAA...97...67H.
  12. ↑ J. V. Scotti (21 October 1993). D. W. Green (ed.). "Periodic Comet Urata–Niijima (1993q)". IAU Circular. 5882 (1).
  13. ↑ Kronk, Meyer & Seargent 2017, pp. 805–806.
  14. ↑ P. L. Lamy; I. Toth; H. A. Weaver; et al. (2000). "The nucleus of 13 short-period comets". Bulletin of the American Astronomical Society. 32: 1061. Bibcode:2000DPS....32.3604L.
  15. ↑ S. Wyckoff; S. Tegler (17 December 1986). D. W. Green (ed.). "Spectroscopic Observations of Comets". IAU Circular. 4284 (3). Bibcode:1986IAUC.4284....3W.

Bibliography

  • Kronk, Gary W.; Meyer, Maik; Seargent, David A. J. (2017). Cometography: A Catalog of Comets. Vol. 6: 1983–1993. Cambridge University Press. ISBN 978-0-521-87216-4.
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