Comet P/2006 XG16 = 2013 R2 (Spacewatch) J. V. Scotti (月惑星研究所:LPL, Arizona大学)の通報によると9月14.48日UT、Spacewatch 1.8-m f/2.7反射望遠鏡で得た画像から恒星状に見える21.6等のP/2006 XG16を検出した。 検出位置は次のとおり、 2013 UT R.A. (2000) Decl. Mag. Observer Sept.14.47695 6 49 21.56 +22 43 49.5 21.6 Scotti 14.48373 6 49 22.32 +22 43 50.0 21.8 " 14.49054 6 49 23.12 +22 43 50.5 22.0 " 15.47784 6 51 15.09 +22 44 25.5 21.5 " 15.48461 6 51 15.85 +22 44 25.6 21.5 " 15.49141 6 51 16.59 +22 44 26.5 21.8 " MPC 75730のB. G. Marsdenの予報に対し、Delta(T)は、+0.27 dayであった。 連結軌道要素、位置推算表は次のとおり、 Orbital elements: P/2006 XG16 = 2013 R2 (Spacewatch) Epoch 2007 Mar. 1.0 TT = JDT 2454160.5 T 2007 Feb. 9.96131 TT MPC q 2.1022092 (2000.0) P Q n 0.14247058 Peri. 41.31178 -0.48834907 -0.85884772 a 3.6306628 Node 78.45364 +0.75348476 -0.50435227 e 0.4209847 Incl. 9.07780 +0.44019984 -0.08949512 P 6.92 From 86 observations 2006 Nov. 15-2013 Sept. 15, mean residual 0".5. P/2006 XG16 = 2013 R2 (Spacewatch) Epoch 2014 Jan. 23.0 TT = JDT 2456680.5 T 2014 Jan. 10.27397 TT MPC q 2.1117580 (2000.0) P Q n 0.14197517 Peri. 41.14848 -0.48566679 -0.86040864 a 3.6391038 Node 78.43676 +0.75511373 -0.50189777 e 0.4197038 Incl. 9.06474 +0.44037600 -0.08829274 P 6.94 From 86 observations 2006 Nov. 15-2013 Sept. 15, mean residual 0".5. P/2006 XG16 = 2013 R2 (Spacewatch) Epoch 2020 Dec. 17.0 TT = JDT 2459200.5 T 2020 Dec. 19.28000 TT MPC q 2.1198487 (2000.0) P Q n 0.14167638 Peri. 41.06071 -0.48397879 -0.86138664 a 3.6442185 Node 78.41144 +0.75611776 -0.50034559 e 0.4182981 Incl. 9.05651 +0.44051159 -0.08756336 P 6.96 From 86 observations 2006 Nov. 15-2013 Sept. 15, mean residual 0".5. P/2006 XG16 = 2013 R2 (Spacewatch) Epoch 2013 Nov. 4.0 TT = JDT 2456600.5 T 2014 Jan. 10.31662 TT MPC q 2.1117195 (2000.0) P Q n 0.14195245 Peri. 41.16251 -0.48591552 -0.86026580 a 3.6394922 Node 78.43936 +0.75496721 -0.50212231 e 0.4197763 Incl. 9.06544 +0.44035283 -0.08840780 P 6.94 From 86 observations 2006 Nov. 15-2013 Sept. 15, mean residual 0".5. Ephemeris: P/2006 XG16 (Spacewatch) Date TT R. A. (2000) Decl. Delta r Elong. Phase m1 m2 2013 08 16 05 52 17.1 +22 00 17 2.8145 2.3813 54.9 20.4 20.5 22.1 ... 2013 08 31 06 21 33.8 +22 29 17 2.6194 2.3337 62.6 22.6 20.3 22.0 ... 2013 09 08 06 37 00.6 +22 38 46 2.5129 2.3097 66.8 23.6 20.1 21.9 ... 2013 09 14 06 48 27.1 +22 43 32 2.4324 2.2923 70.0 24.4 20.0 21.9 2013 09 15 06 50 20.7 +22 44 10 2.4190 2.2895 70.5 24.5 20.0 21.9 2013 09 16 06 52 14.0 +22 44 44 2.4055 2.2867 71.1 24.6 20.0 21.8 ... 2013 09 22 07 03 27.5 +22 47 17 2.3246 2.2702 74.4 25.2 19.9 21.8 ... 2013 09 30 07 18 06.1 +22 48 48 2.2167 2.2493 78.9 25.9 19.7 21.7 ... 2013 10 15 07 44 10.9 +22 49 15 2.0160 2.2134 87.7 26.8 19.5 21.5 Computer: Williams (CBET 3655、MPEC 2013-S01)