OAA computing section circular NK 1213 168P/Hergenrother (1998 W2 = 2005 N2)
The following improved orbital elements, by S. Nakano, are from 96 observations 1998 to 2005. Perturbations by Mercury to Neptune and three minor planets, Ceres, Pallas and Vesta, were taken into account. The mean residual is +/- 0.84 arc seconds. See previous orbits in NK 854 and YC 2477. Epoch = 2005 Nov. 6.0 TT T = 2005 Nov. 2.48016 +/- 0.00061 (m.e.) TT Peri. = 13.87814 +/- 0.00023 Node = 356.50342 +/- 0.00010 (2000.0) Inc. = 21.89402 +/- 0.00006 q = 1.4257646 +/- 0.0000014 AU e = 0.6075136 +/- 0.0000004 a = 3.6326469 +/- 0.0000013 AU n' = 0.14235387 +/- 0.00000008 P = 6.924 +/- 0.0000038 years T = 1998 Dec. 5.94519 TT Epoch = 1998 Dec. 13.0 TT Peri. = 13.88746 e = 0.6084655 Node = 356.50239 (2000.0) a = 3.6272671 AU Inc. = 21.92947 n'= 0.14267069 q = 1.4202000 AU P = 6.908 years The predicted orbit for the 2012 return is as follows: T = 2012 Oct. 1.69866 TT Epoch = 2012 Sept.30.0 TT Peri. = 13.97126 e = 0.6094032 Node = 356.46917 (2000.0) a = 3.6224906 AU Inc. = 21.92990 n'= 0.14295296 q = 1.4149332 AU P = 6.895 years The following residuals in seconds of arc are from the above orbital elements: Date Code Residual(") Date Code Residual(") Date Code Residual(") 1998/ 981213 693 1.7- 0.2- 990214 693 0.9- 0.9- 981121 703 0.4+ 1.8+ 981216 402 1.8+ 1.0+ 990412 693 0.6- 0.3- 981121 703 (2.8+ 2.6+) 981216 402 0.0 0.6- 990412 693 0.2- 0.7- 981122 703 (4.6+ 0.2-) 981216 402 1.1- 0.2+ 990415 693 1.0+ 0.9- 981122 703 (4.6+ 0.3-) 981216 402 1.5- 1.0- 990415 693 1.6+ 0.5- 981122 703 0.6+ 1.2+ 981217 402 0.1+ 0.3+ 990415 693 1.2+ 0.5- 981123 693 0.0 1.0+ 981217 402 0.1+ 0.5- 2005/ 981123 693 0.5- 0.8+ 981217 402 (0.7- 2.1-) 050704 415 0.6- 0.6- 981123 693 0.4- 0.6+ 981219 691 1.1- 0.4- 050704 415 0.4- 0.8- 981123 693 0.1- 1.0+ 981219 691 1.5- 0.9- 050704 415 0.6- 0.5- 981123 691 0.2+ 0.5+ 981223 402 1.7+ 0.3- 050704 415 0.5- 0.9- 981123 691 0.2+ 1.2+ 981223 402 0.4+ 1.6- 050704 415 1.0- 0.7- 981123 360 0.0 0.4+ 981223 402 1.5+ 0.1+ 050705 415 1.3- 0.3- 981123 360 0.3- 0.6+ 981223 402 2.0+ 0.7- 050705 415 0.1- 0.3- 981123 360 0.5+ 0.5+ 981223 118 0.4+ 0.1+ 050705 415 1.2- 0.5+ 981124 691 0.1- 0.8+ 981223 118 0.2+ 0.6- 050705 E12 1.1+ 0.4- 981124 691 0.4- 0.4+ 981223 118 1.1+ 0.6+ 050705 E12 0.9+ 0.3- 981124 691 0.2+ 1.1+ 1999/ 050705 E12 1.2+ 0.7- 981124 709 0.8+ 0.8+ 990105 402 1.2- 0.8- 050705 E12 1.3+ 0.6- 981124 709 0.1+ 0.8+ 990105 402 1.2+ 0.7- 050705 413 0.5+ 0.9- 981124 709 0.6+ 0.9+ 990105 402 1.0- 0.1- 050705 413 0.6+ 0.9- 981124 709 0.7- 0.5+ 990113 360 1.2- 0.5- 050711 415 0.2- 0.4- 981124 709 0.3+ 0.9+ 990113 360 1.7- 1.1- 050711 415 0.4- 0.6- 981124 426 0.2- 1.6+ 990113 360 0.2- 0.5- 050715 415 0.6+ 0.5- 981124 426 0.6- 0.8+ 990114 693 1.4- 0.7- 050715 415 0.5+ 0.2- 981125 402 (0.1- 2.6-) 990114 693 1.6- 1.0- 050727 415 1.5+ 0.1- 981125 402 0.9- 0.4- 990114 693 1.2- 1.0- 050727 415 1.1+ 0.0 981125 402 0.0 0.1+ 990115 693 (0.4- 2.1-) 050728 E12 0.9- 0.7- 981128 402 0.7+ 1.0+ 990115 693 0.2- 1.4- 050728 E12 0.3+ 1.3+ 981128 402 1.2+ 0.5+ 990115 693 0.5- 1.6- 050728 E12 0.1+ 0.2+ 981128 402 0.2- 0.5- 990213 693 1.2- 0.3+ 050728 E12 0.2+ 0.7- 981128 426 1.8+ 0.7- 990213 693 0.8- 0.4- 050730 415 0.6+ 0.3+ 981128 426 1.0+ 0.6- 990213 693 1.1- 0.9- 050730 415 0.9+ 0.1- 981128 426 0.1+ 0.5+ 990214 693 1.4- 1.5- 050731 415 0.6+ 0.0 981213 693 1.4- 0.1+ 990214 693 1.0- 0.5- 050731 415 0.5+ 0.4+ ( ) -------- Rejected Obs.
Director, Computing Section Syuichi Nakano 2005 Aug. 10