Nakano Note (Nakano wa Kangaeru noda) NK 4399 P/Hill (2009 Q1 = 2021 E1)

The following improved orbital elements, by S. Nakano, are from 137 observations 1996 to 2021, including planetary perturbations by Mercury to Neptune and three minor planets, Ceres, Pallas, Vesta, and non-gravitational effect of sublimating molecule = CO (or N2) using Yabushita's theory (MN 283, 347). Gravitational and Water-Ice solutions don't give fine results. The mean residual is +/- 0.82 arc seconds. Pre-discovery observations in 1996 and 1998 were found on code 566 frames. Thus comet has made three appearances. When two night obser- vations in 1998 are included in improvement, the residuals in 1998 show -1" and +8". However the residuals in 1996 and 2021 observations become bad about +3" off. The residuals of recovery observations were +9'.0 for Right Ascension and -0'.6 for Declination from the prediction in NK 3979 (= HICQ 2020/2021), which was computed from 2009 observations only, with the delta-T correction = -1.07 days. Observations in 1996 and 1998 shows the residuals of -23', -3' (delta -T= +1.1 days) and -6', -1' (delta-T= +0.86 day) from the above prediction, resrectively. The comet has passed 1.94 AU from Saturn on 1979 Jan. 15 and 0.86 AU from Jupiter on 1982 Jan. 11 UT. See an orbit in CBET 4943 (same orbit). Epoch = 2022 May 21.0 TT T = 2022 May 22.83870 +/- 0.05212 (m.e.) TT Peri. = 157.12168 +/- 0.00692 Node = 173.95212 +/- 0.00014 (2000.0) Inc. = 14.50431 +/- 0.00006 q = 2.7888365 +/- 0.0000406 AU e = 0.4958300 +/- 0.0000194 a = 5.5315399 +/- 0.0002276 AU n' = 0.07575913 +/- 0.00000468 P = 13.010 +/- 0.0008030 years Y1 = +5.458 +/- 0.995 Y2 = +0.02316 +/- 0.00976 (+/- 0.29 day) T = 1996 Sept.16.29547 TT Epoch = 1996 Oct. 4.0 TT Peri. = 159.16042 e = 0.4968608 Node = 174.31326 (2000.0) a = 5.4842471 AU Inc. = 14.45157 n'= 0.07674119 q = 2.7593400 AU P = 12.843 years T = 2009 July 4.40053 TT Epoch = 2009 June 18.0 TT Peri. = 157.99786 e = 0.4966798 Node = 174.08960 (2000.0) a = 5.5433192 AU Inc. = 14.43713 n'= 0.07551779 q = 2.7900646 AU P = 13.051 years The predicted orbit for the 2035 return is as follows: T = 2035 Feb. 11.47694 TT Epoch = 2035 Feb. 2.0 TT Peri. = 156.36109 e = 0.4937526 Node = 173.10716 (2000.0) a = 5.4586877 AU Inc. = 14.60369 n'= 0.07728082 q = 2.7634466 AU P = 12.754 years The following residuals in seconds of arc are from the above orbital elements: Date Code Residual(") Date Code Residual(") Date Code Residual(") 1996/ 090829 H10 0.4- 1.0- 090919 G96 0.8+ 0.1+ 960715 566 0.1- 0.7- 090829 H06 1.8- 0.4+ 090919 G96 0.9+ 0.4- 960715 566 0.1+ 0.2- 090829 703 1.6- 0.5+ 090919 204 0.4- 0.5- 960715 566 0.1+ 0.2- 090829 H36 0.4- 0.5- 090919 204 0.1+ 0.1- 1998/ 090829 H36 0.6- 0.7- 090920 H06 0.8+ 0.3+ 980126 566(75.1- 7.3+) 090829 704 1.1+ 0.5+ 090920 H06 0.1+ 0.6+ 980226 566(71.9- 4.0+) 090829 703 0.4- 0.4- 090920 H06 0.6- 0.3+ 2009/ 090829 703 1.8- 0.6+ 090920 900 0.1+ 1.3+ 090816 691 0.1+ 1.3+ 090829 704 (0.0 2.2-) 090920 900 1.1- 0.5- 090816 691 0.9- 0.8+ 090829 703 0.7- 0.6+ 090921 585 (1.8+ 2.1-) 090816 691 1.2- 0.8+ 090829 703 (2.3- 0.7-) 090921 585 1.2+ 0.2- 090827 703 (3.2- 2.9+) 090829 704 0.7- 0.0 090921 585 0.6+ 1.5- 090827 703 (3.4- 0.1-) 090829 704 0.7- 0.0 090921 585 0.3+ 0.7- 090827 703 1.0- 1.5+ 090829 A71 (0.1- 2.1-) 090921 585 0.3- 0.9- 090827 703 (3.5- 0.6+) 090829 585 (2.3+ 0.9+) 090923 130 0.7- 0.5- 090827 703 1.0- 1.5+ 090830 585 (3.3+ 0.1+) 090924 A77 1.7+ 1.4+ 090827 703 (2.4- 0.2+) 090831 H45 0.4- 0.2+ 090924 A77 0.8+ 1.0+ 090827 703 (2.8- 0.2-) 090831 H45 0.8- 0.5- 090924 A77 1.4- 1.3+ 090827 703 1.1- 0.0 090831 H45 0.6- 0.6- 090924 A32 1.1- 1.1+ 090828 204 0.3+ 0.2+ 090831 H45 0.5- 1.0+ 090924 A32 0.1- 0.2+ 090828 204 0.5+ 0.6+ 090831 H45 (0.1- 2.2+) 090924 A32 (0.9+ 2.4+) 090828 118 0.3- 0.7+ 090831 H45 (1.7- 2.6+) 090925 585 0.4- 1.0- 090828 118 1.5+ 1.8- 090831 215 1.0- 0.1- 090925 585 0.0 0.2+ 090828 H06 0.7+ 0.0 090831 215 1.4+ 0.4+ 090928 850 (3.3+ 1.2-) 090828 H06 0.5- 0.8- 090831 215 1.8+ 0.8+ 090928 850 0.1+ 0.2+ 090828 H36 0.8- 0.3- 090910 703 0.1- 0.1- 090928 645 0.8+ 0.0 090828 703 (2.8- 0.9-) 090910 703 1.0- 0.6- 090928 645 0.8+ 0.2- 090828 H36 0.3- 1.0- 090910 703 0.2- 1.0- 090928 645 0.4+ 1.7- 090828 703 (2.6- 0.0 ) 090910 703 0.5- 1.4- 091015 645 1.1+ 0.1+ 090828 H36 0.7+ 0.1- 090910 585 0.6- 0.8- 091015 645 1.0+ 0.0 090828 703 (2.3- 1.3+) 090910 585 0.7+ 0.1+ 091015 645 0.8+ 0.2- 090828 703 1.5- 0.6+ 090910 B42 0.2- 0.4- 091016 645 0.8+ 0.3+ 090828 H06 1.0- 0.6- 090911 160 0.4- 0.4+ 091016 645 0.9+ 0.2+ 090828 H06 0.8- 0.7- 090912 213 0.2- 0.5- 091016 645 0.8+ 0.1+ 090828 H06 0.5- 0.7+ 090912 213 0.2- 0.6- 091022 291 0.9+ 1.4+ 090828 H06 0.3- 0.4+ 090912 B90 (3.3- 3.4-) 091022 291 1.0+ 1.0+ 090828 H06 0.8- 0.4+ 090913 A77 1.4+ 0.7+ 091022 291 0.7+ 0.8+ 090828 349 1.0+ 0.1- 090913 A77 1.5+ 1.5- 091024 G96 0.3- 1.3+ 090828 349 1.4+ 0.3+ 090913 A77 0.4- 0.3- 091024 G96 1.5+ 1.2+ 090828 J87 0.0 0.0 090913 J24 0.9+ 1.5- 091024 G96 0.6+ 1.0+ 090828 J87 0.1+ 0.2+ 090914 J24 1.8- 0.3- 091024 G96 0.8+ 0.6+ 090828 J87 0.3+ 0.5+ 090914 J24 0.8+ 0.5- 091025 204 1.3+ 1.2+ 090828 176 0.0 0.6+ 090915 H10 0.7- 0.1+ 091026 850 1.7- 1.3+ 090828 176 1.1+ 0.2+ 090915 H10 0.3+ 0.4- 091026 850 0.6+ 0.8+ 090828 176 0.3+ 0.5+ 090916 A32 0.9+ 0.9- 091111 A77 (0.2- 3.8+) 090828 176 0.4+ 1.2+ 090916 A32 1.6- 1.9+ 091111 A77 1.1+ 1.0+ 090829 A79 0.7+ 0.3+ 090917 G96 0.1- 0.6- 2021/ 090829 A79 0.2- 0.8+ 090917 G96 0.2+ 0.6- 210311 Z84 0.8- 1.0- 090829 H10 (2.1+ 1.1+) 090917 G96 0.1+ 0.1- 210311 Z84 1.1- 0.2+ 090829 H10 1.1- 1.7+ 090917 G96 0.6- 0.4- 210311 Z84 0.4- 0.8- 090829 703 0.9- 0.4- 090918 213 0.3+ 0.8- 210311 Z84 1.3- 0.1+ 090829 703 1.0- 0.4+ 090918 213 0.7+ 1.1- 210314 J04 0.7+ 0.4+ 090829 H06 0.6- 0.0 090918 213 0.4+ 0.6- 210314 J04 1.4+ 1.0+ 090829 703 0.3+ 1.3+ 090919 G96 0.4+ 0.6- 210314 J04 1.6+ 1.0+ 090829 H06 0.7- 0.1- 090919 G96 0.6+ 0.1- ( ) -------- Rejected Obs.

Associate of the CBAT Syuichi Nakano 2021 Mar. 14

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