OAA computing section circular NK 488 Periodic Comet Bus 1981 XI = 1981b
The following improved orbital elements, by S. Nakano, are from 18 observations 1981 Feb. 9 to June 27: Perturbations by all nine planets were taken into account. The mean residual is +/- 1.46 arc seconds. Epoch = 1981 June 5.0 ET T = 1981 June 11.46835 +/- 0.05394 (m.e.) ET Peri. = 24.68092 +/- 0.17548 Node = 181.53133 +/- 0.17477 (1950.0) Inc. = 2.57894 +/- 0.00518 q = 2.1825776 +/- 0.0005428 AU e = 0.3750414 +/- 0.0001129 a = 3.4923553 +/- 0.0005968 AU nß = 0.15101721 +/- 0.00000068 P = 6.526 +/- 0.0016728 years (+/- 0.61 day) The predicted orbit for the 1987 return is as follows: T = 1987 Dec. 21.34285 ET Epoch = 1987 Dec. 31.0 ET Peri. = 24.59751 e = 0.3731337 Node = 181.49394 (1950.0) a = 3.4978249 AU Inc. = 2.57679 nß= 0.15066312 q = 2.1926687 AU P = 6.542 years The following residuals in seconds of arc are from the above orbital elements: Date/ UT R.A. (1950) Decl. *** O-C *** Code/Obs. h m s ¡ , " " " 1981 02 09.64757 11 59 16.76 -01 11 45.8 1.4+ 1.9+ 413/SS 1981 02 13.64028 11 58 57.89 -01 05 50.9 0.8+ 2.0+ 413/SS 1981 03 02.60104 11 53 27.48 -00 09 12.9 0.9+ 1.9- 413/SS 1981 03 03.58906 11 52 57.36 -00 04 30.5 0.9+ 1.3- 413/SS 1981 03 04.17280 11 52 39.27 -00 01 47.6 2.9+ 0.6- 801/HO 1981 03 04.22568 11 52 37.30 -00 01 32.0 0.0 0.6- 801/HO 1981 03 05.70174 11 51 49.43 +00 05 54.0 1.2- 2.7+ 372/sk 1981 03 05.71979 11 51 48.70 +00 05 59.7 2.7- 2.9+ 372/sk 1981 03 07.62836 11 50 44.45 +00 15 57.6 1.4- 0.1- 413/SS 1981 03 09.60486 11 49 35.12 +00 26 27.7 0.4+ 1.0- 372/sk 1981 03 11.20264 11 48 37.00 +00 35 16.8 0.5+ 1.8- 801/HO 1981 03 11.67118 11 48 19.47 +00 37 56.4 1.9- 0.9- 372/sk 1981 03 16.71113 11 45 08.14 +01 07 08.5 0.9- 1.3- 413/SS 1981 04 03.43473 11 34 23.95 +02 47 55.8 ( 2.6- 6.2+) 474/JN 1981 04 03.46131 11 34 23.12 +02 48 03.5 ( 2.0- 5.8+) 474/JN 1981 04 25.20729 11 28 32.53 +04 00 52.1 0.1- 0.1+ 675/PL 1981 05 23.08895 11 39 24.45 +03 24 06.6 0.6- 0.9- 801/HO 1981 05 24.11951 11 40 11.23 +03 20 03.2 1.3+ 0.1- 801/HO 1981 06 06.11803 11 51 56.23 +02 14 36.8 0.5- 0.8- 801/HO 1981 06 27.09139 12 17 10.94 -00 16 34.0 1.0+ 2.9+ 801/HO ( ) -------- Rejected Obs.
Director, Computing Section Syuichi Nakano 1985 December 22