Comet C/2019 LB7 (Kleyna) 6月21日、Jan KleynaとMarco Micheliの通報によると、6月7.6日、8.6日と9.6日UT、Kleynaが、 Mauna Keaにある8.2-m すばる望遠鏡のHuper-SuprimeCamで得たCCD画像から非常に暗い彗星を 発見した。この天体は拡散して南西へ約1" 伸びているようだ。 R. Werykの書き込みによると、7月1.6日UT、R. Wainscoat、C. WipperとT. Burdullisが、Mauna Keaにある3.6-m Canada-France-Hawaii 望遠鏡で得た3回の180-秒 gri-バンド確認露出では、 南西に向かって約6"の尾が見え、この彗星の頭部は約0".9(半値全幅:FWHM)で、比較した近傍の 恒星のFWHMは0".7であった。非常に暗い天体であったため、精測位置はMPEC 2019-N20に発表され たが、小惑星センタ―の不注意によって小惑星符号2019 LB7与えられていた。 発見位置は次のとおり、 2019 UT R.A. (2000) Decl. Mag. Observer June 7.59119 1 19 14.22 + 8 28 20.2 23.4 Kleyna 7.60241 1 19 13.93 + 8 28 21.8 23.1 " 7.61368 1 19 13.63 + 8 28 23.5 23.6 " 8.59030 1 18 48.54 + 8 30 38.4 23.2 " 8.59872 1 18 48.31 + 8 30 39.4 23.2 " 8.60715 1 18 48.09 + 8 30 40.6 23.4 " 8.61557 1 18 47.84 + 8 30 41.8 23.1 " 9.58849 1 18 21.64 + 8 32 51.5 23.1 " 9.59694 1 18 21.40 + 8 32 52.7 23.4 " 9.60539 1 18 21.17 + 8 32 53.8 22.8 " 9.61400 1 18 20.92 + 8 32 54.9 23.0 " 楕円軌道要素と位置推算表は次のとおり、 Orbital elements: C/2019 LB7 (Kleyna) Epoch 2019 Mar. 18.0 TT = JDT 2458560.5 T 2019 Mar. 26.85767 TT MPCLINUX q 2.4788851 (2000.0) P Q n 0.00518759 Peri. 335.74335 +0.88772901 +0.46010662 a 33.0490347 Node 3.26334 +0.45417045 -0.88077928 e 0.9249937 Incl. 164.23837 +0.07527552 -0.11193641 P 190 From 14 observations 2019 June 7-July 1, mean residual 0".1. C/2019 LB7 (Kleyna) Epoch 2019 Apr. 27.0 TT = JDT 2458600.5 T 2019 Mar. 26.85485 TT MPCLINUX q 2.4788843 (2000.0) P Q n 0.00519344 Peri. 335.74278 +0.88772155 +0.46012095 a 33.0242119 Node 3.26371 +0.45418480 -0.88077259 e 0.9249374 Incl. 164.23810 +0.07527699 -0.11193010 P 190 From 14 observations 2019 June 7-July 1, mean residual 0".1. Ephemeris: Date TT R. A. (2000) Decl. Delta r Elong. Phase m1 2019 06 02 01 21 16.6 +08 14 13 3.1242 2.5766 49.1 17.3 23.6 ... 2019 06 17 01 14 20.0 +08 46 52 2.8891 2.6233 64.8 20.5 23.5 ... 2019 06 25 01 08 23.8 +08 56 11 2.7497 2.6515 73.8 21.6 23.4 ... 2019 07 01 01 02 38.4 +08 58 16 2.6415 2.6741 80.8 22.0 23.4 2019 07 02 01 01 33.5 +08 58 09 2.6233 2.6780 82.0 22.1 23.4 2019 07 03 01 00 26.3 +08 57 52 2.6051 2.6819 83.2 22.1 23.4 ... 2019 07 09 00 52 53.5 +08 52 47 2.4960 2.7060 90.7 22.1 23.3 ... 2019 07 17 00 40 23.4 +08 35 29 2.3542 2.7398 101.2 21.3 23.2 ... 2019 08 01 00 08 18.9 +07 20 43 2.1211 2.8083 123.2 17.6 23.1 This object, which was reported as being a comet, was inadvertently designated and announced as minor planet 2019 LB7 on MPEC 2019-N20. It is being reclassified as a comet based on the following reports. J. Kleyna and M. Micheli, in the discovery images from June 6, 8 and 9, noted a diffuse appearance and a possible ~1" elongation to the SW. R. Weryk and R. Wainscoat described their images from July 1 as having a FWHM of ~0".9 (compared to 0".71 ± 0".10 for nearby stars) and a ~6" tail towards the SW. (CBET 4647、MPEC 2019-N32)