Nakano Note (Nakano wa Kangaeru noda) NK 5438 P/PANSTARRS (2012 T2 = 2025 O3)
The following improved orbital elements, by S. Nakano, are from 74 observations 2012 to 2025. Perturbations by Mercury to Neptune and three minor planets, Ceres, Pallas and Vesta, were taken into account. The mean residual is +/- 0.53 arc second. Identification by T. Kobayashi. Because of the short arc (only 34 days), residuals on 2025 July 24 observations were +1.80 deg for Right Ascension and +0.76 deg for Declination from the prediction in HICQ 2013 (= CH 2025) with the delta-T correction = -17.9 days. The comet has passed 3.41 AU from Saturn on 1999 Oct. 27 and passed 0.060 AU from Jupiter on 2001 May 18 UT, before this close approach, comet had an orbit of T= 1984 05 13, q= 4.91 AU, e= 0.28, Peri.= 15.3, Node= 98.5, i= 6.9, a= 6.84 AU, P= 17.9 years. See the previous orbits in HICQ 2013, NK 5432 and CBET 5609 (same orbit). Epoch = 2026 Nov. 16.0 TT T = 2026 Dec. 5.39059 +/- 0.30729 (m.e.) TT Peri. = 308.77084 +/- 0.03336 Node = 73.72172 +/- 0.00130 (2000.0) Inc. = 12.57060 +/- 0.00004 q = 4.8014780 +/- 0.0002427 AU e = 0.1567662 +/- 0.0000434 a = 5.6941243 +/- 0.0004108 AU n' = 0.07253768 +/- 0.00000785 P = 13.588 +/- 0.0014706 years (+/- 0.54 day) T = 2013 Mar. 25.81236 TT Epoch = 2013 Mar. 9.0 TT Peri. = 307.69903 e = 0.1567736 Node = 73.78536 (2000.0) a = 5.7259572 AU Inc. = 12.55822 n'= 0.07193362 q = 4.8282784 AU P = 13.702 years The predicted orbit for the 2040 return is as follows: T = 2040 May 28.45406 TT Epoch = 2040 June 15.0 TT Peri. = 308.21134 e = 0.1562083 Node = 73.59936 (2000.0) a = 5.6517922 AU Inc. = 12.59209 n'= 0.07335417 q = 4.7689356 AU P = 13.436 years The following residuals in seconds of arc are from the above orbital elements: Date Code Residual(") Date Code Residual(") Date Code Residual(") 2012/ 121017 568 0.3+ 0.0 250817 F51 0.4+ 0.1+ 121010 F51 0.2- 0.1- 121017 568 0.3+ 0.0 250817 F51 0.4- 0.2- 121010 F51 0.0 0.2- 121017 568 0.3+ 0.0 250818 T14 0.2+ 1.0- 121010 F51 0.2- 0.0 121021 372 0.0 0.4+ 250818 T14 0.2+ 0.6- 121010 F51 0.1- 0.2- 121021 372 0.0 0.7+ 250818 T14 0.2+ 0.5- 121011 H06 0.7- 0.9+ 121021 372 0.3+ 0.5+ 250818 Q62 0.1- 0.2- 121011 H06 1.3- 0.9+ 121022 C10 1.0- 0.5+ 250818 Q62 0.2- 0.3- 121011 H06 1.9- 0.8+ 121022 C10 0.8+ 0.1+ 250822 W62 1.0- 1.7+ 121011 F65 0.0 0.1- 121107 215 0.6- 1.2+ 250822 W62 1.5- 0.2- 121011 F65 0.1- 0.1- 121107 215 0.5- 0.8+ 250915 I41 0.5- 0.1+ 121013 291 0.1- 1.3+ 121107 215 0.7- 0.3+ 250915 I41 (2.5- 0.2+) 121013 291 0.3+ 0.4+ 121113 H06 1.2- 1.3+ 250916 I41 1.0+ 0.2+ 121014 291 0.5- 1.0+ 121113 H06 1.1- 1.2+ 250917 I41 0.6- 0.3+ 121014 291 0.3+ 0.9+ 2025/ 250918 F51 0.2+ 0.1- 121014 291 0.1+ 0.3+ 250724 F51 0.4- 0.0 250918 F51 0.0 0.2- 121014 H06 0.7- 0.7+ 250724 F51 0.2- 0.2+ 250918 F51 0.1- 0.4+ 121014 H06 1.1- 0.7+ 250724 F51 0.0 0.4+ 250918 F51 0.3+ 0.1+ 121014 568 0.4+ 0.2- 250724 F51 0.2+ 0.3+ 250918 F51 0.1+ 0.1- 121014 568 0.2+ 0.2- 250802 F52 0.1+ 0.0 250918 F51 0.1- 0.3- 121015 304 0.1+ 0.1- 250802 F52 0.0 0.1+ 250919 807 0.0 0.2+ 121015 304 0.0 0.1+ 250802 F52 0.1+ 0.1+ 250919 807 0.1+ 0.0 121015 304 0.1+ 0.2- 250817 F51 0.1- 0.2+ 250919 807 0.1+ 0.6+ 121015 304 0.1+ 0.2- 250817 F51 0.2- 0.1- 250919 X03 0.2+ 0.2+ 121015 J04 0.4+ 1.0+ 250817 F51 0.0 0.2+ 250919 X03 0.1- 0.1- 121015 J04 0.6- 0.5+ 250817 F51 0.2- 0.1- 250919 X03 0.5- 0.2- 121015 J04 0.3- 0.0 250817 F51 0.0 0.1- ( ) -------- Rejected Obs.
Associate of the CBAT Late edition Syuichi Nakano 2025 Sept. 20