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. At the time, it was a 16th-magnitude object within the constellation Aries. Four days later, Tsutomu Seki would confirm the object's cometary nature after spotting a very faint, diffuse coma on 3 November 1986. Further observations by Miklós Lovas and orbital calculations by Brian G. Marsden determined the periodic nature of Urata–Niijima on 17 November 1986. Its brightness remained consistent at roughly 15–16 throughout the entire apparition. The comet was last observed by Tom Gehrels on 27 March 1987.
On August 1987, Shuichi Nakano would later link two asteroids, and , as the same object as Comet Urata–Niijima.
Subsequent apparitions The comet was recovered by James V. Scotti at the Kitt Peak Observatory on 20 October 1993. 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. Philippe L. Lamy and Harold A. Weaver used the Hubble Space Telescope to recover the comet on its next apparition on 4 March 2000.
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 , assuming a geometric albedo of 0.04. During its 1983 apparition, emissions of CN, and were detected from Urata–Niijima's coma.
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Bibliography
External links
at the Minor Planet Center database 112P/Urata–Niijima at Gary W. Kronk's Cometography 112P/Urata–Niijima at Kazuo Kinoshita's Comets 112P/Urata–Niijima at Seiichi Yoshida's website 112P/Urata–Niijima at Gideon van Buitenen's website