OAA computing section circular NK 844 P/1998 X1 (ODAS)
The following improved orbital elements, by S. Nakano, are from 157 observations 1998 Dec. 15 to 1999 Apr. 14. Perturbations by Mercury to Neptune and three minor planets, Ceres, Pallas and Vesta, were taken into account. The mean residual is +/- 0.58 arc second. Comet will pass 0.15 AU near Jupiter on 2042 Oct. 16. Epoch = 1998 July 6.0 TT T = 1998 July 20.93339 +/- 0.00480 (m.e.) TT Peri. = 68.79964 +/- 0.00213 Node = 358.83847 +/- 0.00201 (2000.0) Inc. = 1.35215 +/- 0.00005 q = 1.9744683 +/- 0.0000354 AU e = 0.4479630 +/- 0.0000275 a = 3.5766954 +/- 0.0000530 AU n' = 0.14570724 +/- 0.00000324 P = 6.764 +/- 0.0001503 years (+/- 0.05 day) The predicted orbit for the 2005 return is as follows: T = 2005 May 2.52901 TT Epoch = 2005 Apr. 20.0 TT Peri. = 69.02995 e = 0.4470285 Node = 358.74886 (2000.0) a = 3.5825151 AU Inc. = 1.34951 n'= 0.14535234 q = 1.9810287 AU P = 6.781 years The following residuals in seconds of arc are from the above orbital elements: Date Code Residual(") Date Code Residual(") Date Code Residual(") 1998/ 981218 402 0.8- 0.4+ 990126 360 0.2+ 0.3+ 981215 910 0.3+ 0.5- 981218 402 0.6- 0.2+ 990126 360 0.3- 0.1- 981215 910 0.2- 1.0- 981218 402 0.3+ 0.0 990126 360 0.3+ 0.0 981215 910 0.5+ 0.9- 981218 402 0.4- 0.5+ 990205 897 0.5+ 0.2+ 981216 046 0.5- 0.2+ 981219 897 0.8- 1.7- 990205 897 0.7- 1.0- 981216 046 0.8- 0.7- 981219 897 (3.2- 1.8-) 990206 402 0.2+ 0.6- 981216 046 0.5+ 1.1- 981219 372 (1.1+ 2.1+) 990206 402 0.7+ 0.1- 981216 557 0.5- 0.6- 981219 372 0.7+ 1.7+ 990206 402 1.1+ 0.7+ 981216 910 0.4+ 0.4- 981220 897 (3.6- 0.3-) 990208 402 1.3+ 0.5- 981216 046 0.6- 1.3- 981221 372 (2.6+ 0.4+) 990208 402 1.4+ 0.1- 981216 046 1.1- 1.6- 981221 360 0.8+ 0.7+ 990208 402 1.2+ 0.5- 981216 910 0.2+ 0.3- 981221 360 0.6+ 0.1+ 990213 691 0.5- 0.0 981216 910 0.0 0.5- 981221 360 0.0 0.3+ 990213 691 0.7- 0.0 981216 910 0.2- 0.7- 981222 958 0.6+ 0.8+ 990213 691 0.1+ 0.3+ 981216 910 0.4- 1.3- 981222 958 0.8- 0.4+ 990213 691 0.3- 0.1- 981216 586 0.7+ 0.1+ 981222 958 0.4+ 0.1- 990213 691 0.8- 0.7+ 981216 910 0.1- 0.8- 981224 360 0.1- 0.0 990213 691 0.5- 0.3- 981216 586 0.5+ 0.4+ 981224 360 0.4- 0.5+ 990213 691 0.8- 1.0+ 981216 586 0.6+ 0.1+ 981224 360 0.5+ 0.0 990213 691 0.4- 0.0 981216 586 0.7+ 0.4+ 981226 910 0.0 0.4- 990213 691 0.5+ 0.8+ 981216 586 0.5+ 0.2+ 981227 958 (0.0 3.9+) 990214 693 0.1+ 0.1- 981216 586 0.3+ 0.1+ 981227 958 1.8- 0.5+ 990214 693 0.2+ 0.1- 981216 586 0.3+ 0.3+ 981227 402 0.4+ 0.1- 990214 693 0.1+ 0.1- 981216 586 0.4+ 0.3+ 981227 402 0.2+ 0.5- 990214 360 0.1+ 0.4- 981216 586 0.7+ 0.3+ 981227 402 0.7+ 0.1+ 990214 360 0.3+ 0.1- 981216 586 0.7+ 0.2+ 1999/ 990214 360 0.1+ 0.5- 981216 586 0.5+ 0.3+ 990107 897 1.6- 1.7+ 990215 118 0.2+ 0.2- 981216 586 0.6+ 0.4+ 990107 897 0.2+ 1.4+ 990215 118 0.2- 0.4+ 981216 586 0.6+ 0.4+ 990107 897 0.4- 1.6+ 990216 691 0.8- 0.3- 981216 611 0.1+ 0.9- 990110 372 0.4- 1.3+ 990216 691 0.2- 0.2+ 981217 611 (2.7- 0.9-) 990113 693 0.6- 0.1+ 990216 691 1.2- 0.1- 981217 586 0.6- 0.1+ 990113 693 0.7- 0.1+ 990216 615 0.4+ 0.6+ 981217 586 0.1+ 0.1+ 990113 693 0.5- 0.0 990216 615 0.8+ 0.1- 981217 046 0.9- 0.5- 990114 910 0.8+ 0.1+ 990216 615 0.1- 0.3+ 981217 586 0.1- 0.2- 990114 910 0.9+ 0.4- 990216 615 0.3+ 0.3+ 981217 046 0.8- 0.2+ 990114 910 0.5- 0.8- 990216 615 0.1- 0.2+ 981217 046 0.3+ 0.2- 990115 910 0.1+ 0.8- 990216 615 0.2- 0.0 981217 586 0.0 0.1+ 990115 910 0.6+ 0.7- 990216 615 0.4- 0.2+ 981217 046 0.2+ 0.1- 990115 910 0.7+ 1.2- 990216 615 0.8- 0.9+ 981217 046 0.7+ 0.2- 990115 910 0.1- 1.4- 990216 615 0.2+ 0.3+ 981217 586 0.5- 0.0 990115 910 0.2+ 1.3- 990216 615 0.1+ 0.7+ 981217 586 0.2- 0.2+ 990115 910 0.3- 0.5- 990216 615 0.1- 0.7+ 981217 586 0.5- 0.3+ 990115 910 0.2- 1.0- 990216 615 0.6- 0.5+ 981217 586 0.3- 0.1+ 990119 910 0.1+ 0.5+ 990216 615 0.2- 0.4+ 981217 586 0.5- 0.3+ 990119 910 0.3+ 0.3+ 990216 615 0.2- 0.3+ 981217 586 0.7- 0.0 990119 910 0.3+ 0.1+ 990216 615 0.2+ 0.7+ 981217 586 0.2- 0.3+ 990119 910 0.5- 0.1+ 990223 897 (1.4+ 2.7+) 981217 586 0.0 0.0 990119 910 0.0 0.3+ 990223 897 (3.4+ 0.0 ) 981218 511 0.2+ 0.4+ 990119 910 0.1- 0.3+ 990223 897 0.7+ 0.8- 981218 511 0.0 0.4+ 990119 910 0.2- 0.2+ 990316 402 0.7+ 0.1+ 981218 511 0.1- 0.2+ 990119 910 0.0 0.4+ 990316 402 (0.5+ 2.6-) 981218 511 0.1- 0.3+ 990119 910 0.1+ 0.1+ 990316 402 0.9- 1.4- 981218 511 0.1- 0.3+ 990119 910 0.2- 0.7+ 990404 402 0.4- 0.4- 981218 511 0.1+ 0.4+ 990121 360 0.5+ 0.5- 990404 402 1.2+ 0.7- 981218 511 0.1- 0.4+ 990121 360 0.4+ 0.1- 990414 693 0.8- 1.2- 981218 511 0.1- 0.5+ 990121 360 0.0 0.2- 990414 693 (3.6- 0.1+) 981218 511 0.1- 0.8- 990126 402 (2.1+ 1.0+) ( ) -------- Rejected Obs.
Director, Computing Section Syuichi Nakano 2002 May 7