OAA computing section circular NK 539 Periodic Comet Gehrels 3
The following improved orbital elements, by S. Nakano, are from 48 observations 1975 to 1987. Perturbations by all nine planets were taken into account. The mean residual is +/- 0.90 arc second. Epoch = 1985 May 15.0 ET T = 1985 June 3.37255 +/- 0.00257 (m.e.) ET Peri. = 231.30358 +/- 0.00595 Node = 242.44687 +/- 0.00595 (1950.0) Inc. = 1.09977 +/- 0.00010 q = 3.4422414 +/- 0.0000018 AU e = 0.1492904 +/- 0.0000004 a = 4.0463179 +/- 0.0000005 AU nß = 0.12109161 +/- 0.00000002 P = 8.139 +/- 0.0000016 years T = 1977 Apr. 23.18454 ET Epoch = 1977 Apr. 7.0 ET Peri. = 231.47727 e = 0.1518978 Node = 242.54794 (1950.0) a = 4.0376642 AU Inc. = 1.10125 nß= 0.12148112 q = 3.4243518 AU P = 8.113 years The predicted orbit for the 1993 return is as follows: T = 1993 July 25.42080 ET Epoch = 1993 Aug. 1.0 ET Peri. = 231.87906 e = 0.1507477 Node = 242.33098 (1950.0) a = 4.0353166 AU Inc. = 1.10250 nß= 0.12158714 q = 3.4270021 AU P = 8.106 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 ¡ , " " " 1975 10 27.14534 01 51 39.58 +12 17 59.6 0.4+ 1.7- 675/PL 1975 10 28.15645 01 51 00.93 +12 14 13.4 ( 2.3+ 2.6-) 675/PL 1975 10 30.14568 01 49 44.82 +12 06 53.4 0.2- 1.0+ 675/PL 1975 11 07.16956 01 44 48.10 +11 37 30.3 1.1+ 1.2+ 801/HO 1975 11 09.15630 01 43 38.38 +11 30 28.6 0.1- 1.1+ 801/HO 1975 11 10.10184 01 43 06.05 +11 27 11.7 0.9+ 1.8+ 801/HO 1975 11 30.04437 01 34 06.99 +10 30 02.5 0.7- 0.6+ 801/HO 1975 11 30.04437 01 34 07.08 +10 30 02.0 0.6+ 0.1+ 801/HO 1975 12 07.20903 01 32 19.15 +10 17 21.2 1.3+ 0.7+ 693/CT 1975 12 07.23264 01 32 18.87 +10 17 19.3 1.5+ 0.9+ 693/CT - continued - P/Gehrels 3 NK 539 - 2 Date/ UT R.A. (1950) Decl. *** O-C *** Code/Obs. h m s ¡ , " " " 1975 12 08.15354 01 32 08.65 +10 16 03.1 0.6- 1.3+ 801/HO 1975 12 29.04925 01 32 18.75 +10 10 24.4 1.7- 1.8+ 801/HO 1976 01 27.18733 01 44 29.24 +11 11 49.0 0.2- 0.5+ 691/ST 1976 02 25.01155 02 07 18.98 +13 09 26.4 1.5+ 1.8- 801/HO 1976 02 26.02105 02 08 15.82 +13 14 14.7 1.8- 0.2- 801/HO 1976 10 23.38262 06 41 29.43 +22 38 09.1 0.4- 0.7- 801/HO 1976 11 20.36187 06 41 03.52 +22 28 53.7 1.2- 0.4+ 801/HO 1976 11 24.35208 06 39 38.90 +22 28 51.0 0.9- 0.2- 693/CT 1976 11 24.38819 06 39 38.05 +22 28 51.3 0.2- 0.0 693/CT 1976 12 16.30740 06 26 58.37 +22 31 49.0 1.2- 0.3+ 801/HO 1976 12 24.41181 06 20 56.09 +22 33 09.7 0.7- 0.3- 693/CT 1976 12 24.44375 06 20 54.60 +22 33 10.0 0.7- 0.1- 693/CT 1977 01 13.18484 06 06 32.69 +22 34 26.1 1.4- 0.1- 801/HO 1977 02 16.05826 05 55 04.48 +22 34 01.4 1.4- 0.1+ 801/HO 1977 03 22.05812 06 07 33.91 +22 36 05.1 ( 3.9- 2.4+) 801/HO 1977 11 18.40129 10 59 09.30 +05 21 43.8 0.9+ 0.3- 801/HO 1977 12 11.37934 11 15 04.81 +03 34 45.9 0.7- 0.6+ 801/HO 1978 02 03.73159 11 20 05.53 +02 44 35.3 ( 3.3- 1.6-) 323/PR 1978 02 06.77639 11 18 52.11 +02 51 36.4 ( 1.4- 4.2-) 323/PR 1978 02 11.26175 11 16 49.45 +03 03 40.1 0.2+ 0.1- 801/HO 1978 03 02.62371 11 05 39.23 +04 12 24.6 1.3+ 0.6+ 381/ks 1978 03 02.66266 11 05 37.64 +04 12 33.4 0.3+ 0.0 381/ks 1978 03 05.56125 11 03 47.19 +04 24 10.6 1.4+ 1.0- 381/ks 1978 03 12.62442 10 59 18.93 +04 52 40.3 0.0 0.1- 885/ur 1978 03 12.65069 10 59 17.98 +04 52 45.3 0.9+ 1.4- 885/ur 1978 03 31.83189 10 48 49.91 +06 01 35.4 ( 2.8+ 1.8-) 046/KL 1978 04 07.55208 10 46 11.32 +06 19 59.7 ( 2.6- 2.0+) 323/PR 1978 04 13.65000 10 44 24.3 +06 32 59 ( 0.1+ 2.6+) 372/sk Y 1978 05 09.54861 10 43 50.98 +06 46 43.5 0.1+ 0.9+ 323/PR 1984 08 07.45975 05 12 24.04 +22 56 23.8 0.3+ 0.4- 675/PL 1984 08 08.45489 05 13 32.65 +22 57 31.7 0.7- 0.1+ 675/PL 1985 12 19.43360 10 51 24.99 +05 57 33.3 1.7+ 0.8- 691/ST 1985 12 19.45022 10 51 25.22 +05 57 31.5 0.8+ 0.4- 691/ST 1985 12 19.47105 10 51 25.56 +05 57 28.4 0.6+ 0.7- 691/ST 1986 01 16.50956 10 52 49.68 +05 38 08.3 1.3+ 0.3- 691/ST 1986 01 16.52560 10 52 49.46 +05 38 09.9 1.2+ 0.5+ 691/ST 1987 05 01.34394 14 04 45.70 -13 22 09.0 0.0 0.1- 691/ST 1987 05 01.38485 14 04 44.21 -13 21 59.8 0.9+ 0.6+ 691/ST 1987 05 01.38961 14 04 43.96 -13 21 59.0 0.2- 0.4+ 691/ST 1987 05 23.23774 13 53 01.01 -12 13 52.3 0.8- 1.0+ 691/ST 1987 05 23.29214 13 52 59.57 -12 13 43.4 0.7- 1.3+ 691/ST 1987 05 23.29725 13 52 59.39 -12 13 42.5 1.3- 1.4+ 691/ST 1987 05 24.26917 13 52 34.93 -12 11 13.6 0.3- 0.5+ 691/ST 1987 05 24.28271 13 52 34.56 -12 11 11.8 0.6- 0.2+ 691/ST 1987 05 24.29691 13 52 34.16 -12 11 08.7 1.1- 1.1+ 691/ST ( ) -------- Rejected Obs.
Director, Computing Section Syuichi Nakano 1990 May 2