112P/Urata-Niijima (0112P)


Type: Periodic Perihelion date: 7 February 2020 Perihelion distance (q): 1.4 Aphelion distance (Q) : 5.6 Period (years): 6.6 Eccentricity (e): 0.59 Inclination (i): 24.2 JPL orbit diagram COBS lightcurve IAU Circular 4267 (3 November 1986) announced that T. Niijima and T. Urata had discovered a fast-moving minor planet on plates exposed on 30 October 1986 with a 0.30-m f/5.8 reflector at Ojima. The magnitude was estimated as 16. On 5 November, it was announced that T. Seki (Geisei, Japan) had observed the comet on 3 November and noted a "very faint and diffuse coma surrounding a central condensation." M. Lovas independently discovered the object at Piszkesteto on 4 November and described it as asteroidal with a "faint asymmetric coma." A prediscovery photograph from 29 October was also found at Brorfelde. Having passed closest to both the sun and Earth, the comet began fading shortly after discovery. The comet was recovered by James V. Scotti (Kitt Peak, Arizona, USA) using the Spacewatch telescope on 20 October 1993. The precise position indicated the prediction required a correction of only -0.24 day. The comet then showed a coma 11 arc seconds across, which contained a nucleus of magnitude 22.7. A tail extended 0.4 arc minute toward PA 290-292 degrees. The comet was next predicted to arrive at perihelion on 4 March 2000. It was recovered on 8 September 1999 by P. L. Lamy and H. A. Weaver, while using the Hubble Space Telescope for a survey to determine the radius of the nucleus of several comets. In this case, the radius was given as 0.90 kilometers. An independent recovery was made on 13 November 1999, when C. Hergenrother (Kitt Peak, Arizona, USA) gave the magnitude as 21.5. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 16-Jan-20 18.54 0.20 17.1 0.3 24-Jan-20 17.63 0.07 14.7 0.6 21-Feb-20 17.28 0.05 15.3 0.6 09-Mar-20 17.53 0.22 17.0 0.3