Comet P/2006 R1 = 2019 S1 (Siding Spring) P/2006 R1 ((IAUC 8744, 8747を参照)は、G. V. WilliamsとR. Werykによって、9月25日-26日、 Haleakalaにある1.8-m Pan-STARRS1望遠鏡で得た画像から検出した。R. Werykは、9月26日に 得た画像ではこの彗星は本質的に恒星状であると注記した。 中野主一氏のICQ Comet Handbook 2019 (およびNK 1451)の予報に対しDelta(T)は、+6.0 daysで あった。また、MPC 105244のG. V. Williamsの予報に対するDelta(T)は、-6.6 daysであった。 検出位置は次のとおり、 2019 UT R.A. (2000) Decl. Mag. Sept.25.52539 2 43 31.88 + 3 53 41.8 20.5 25.53811 2 43 28.38 + 3 53 04.3 20.4 25.55084 2 43 24.86 + 3 52 26.8 20.3 25.56358 2 43 21.33 + 3 51 49.2 20.4 26.55128 2 38 45.62 + 3 02 15.9 20.5 26.56436 2 38 41.85 + 3 01 35.8 20.4 26.57734 2 38 38.11 + 3 00 56.0 20.5 MPCの連結軌道要素と位置推算表は次のとおり、 Orbital elements: P/2006 R1 (Siding Spring) Epoch 2006 Sept. 22.0 TT = JDT 2454000.5 T 2006 Sept. 3.67388 TT Williams q 1.6711048 (2000.0) P Q n 0.07400939 Peri. 249.30973 +0.82487623 -0.52348001 a 5.6183849 Node 218.63313 -0.30049674 -0.72579389 e 0.7025649 Incl. 160.01117 -0.47883287 -0.44630920 P 13.3 From 65 observations 2006 Sept. 1-2019 Sept. 26, mean residual 0".4. P/2006 R1 (Siding Spring) Epoch 2019 Dec. 23.0 TT = JDT 2458840.5 T 2019 Dec. 29.28442 TT Williams q 1.6633360 (2000.0) P Q n 0.07382745 Peri. 249.29762 +0.82684873 -0.52021008 a 5.6276121 Node 218.83801 -0.29821369 -0.72778834 e 0.7044331 Incl. 160.06864 -0.47685403 -0.44688433 P 13.4 From 65 observations 2006 Sept. 1-2019 Sept. 26, mean residual 0".4. P/2006 R1 (Siding Spring) Epoch 2033 May 3.0 TT = JDT 2463720.5 T 2033 May 3.18548 TT Williams q 1.6607465 (2000.0) P Q n 0.07372956 Peri. 249.12138 +0.82876185 -0.51705543 a 5.6325917 Node 218.87964 -0.29537022 -0.72902767 e 0.7051541 Incl. 160.06358 -0.47530014 -0.44852239 P 13.4 From 65 observations 2006 Sept. 1-2019 Sept. 26. P/2006 R1 (Siding Spring) Epoch 2019 Apr. 27.0 TT = JDT 2458600.5 T 2019 Dec. 29.26079 TT Williams q 1.6634130 (2000.0) P Q n 0.07378577 Peri. 249.28626 +0.82695239 -0.52005167 a 5.6297308 Node 218.83752 -0.29808886 -0.72784829 e 0.7045306 Incl. 160.06993 -0.47675233 -0.44697107 P 13.4 From 65 observations 2006 Sept. 1-2019 Sept. 26, mean residual 0".4. Ephemeris: Date TT R. A. (2000) Decl. Delta r Elong. Phase m1 2019 08 28 03 55 02.6 +17 22 54 1.8103 2.1317 93.9 28.2 20.6 ... 2019 09 12 03 29 44.3 +12 20 56 1.3939 2.0390 115.3 26.5 19.8 ... 2019 09 20 03 05 55.4 +07 57 17 1.1955 1.9920 129.6 22.9 19.4 ... 2019 09 26 02 41 21.2 +03 30 14 1.0693 1.9580 141.8 18.5 19.1 2019 09 27 02 36 37.0 +02 39 14 1.0509 1.9525 143.9 17.6 19.0 2019 09 28 02 31 41.3 +01 46 23 1.0333 1.9470 146.1 16.7 19.0 ... 2019 10 04 01 58 05.3 -04 06 20 0.9490 1.9147 158.3 11.1 18.7 ... 2019 10 12 01 04 06.5 -12 46 16 0.9042 1.8739 160.1 10.4 18.5 ... 2019 10 27 23 20 15.5 -25 03 02 1.0377 1.8051 125.3 26.7 18.6 This comet has been recovered, independently, by the undersigned and by R. Weryk in images reported from the Pan-STARRS 1 telescope (F51). Weryk reported that the comet is essentially stellar in images taken on Sept. 26. The indicated delta-T correction to the prediction, by the undersigned, on MPC 105244, is -6.6 days. (CBET 4671、MPEC 2019-S105)