Comet P/2000 S4 = 2019 K2 (LINEAR-Spacewatch)

G. V. Williams (小惑星センター)の通報によると、5月29日、Pan-STARRS 1サーベイでHaleakala
にある1.8-m Ritchey-Chretien 反射望遠鏡と6月1日、Mt. Lemmonサーベイの1.5-m 反射望遠鏡 
(観測者:B. M. Africano)による観測からP/2000 S4 (IAUCs 7502, 7553を参照)を検出した。
外観の詳細は明らかにされなかった。
MPC 102107のWilliamsの予報に対する修正値は、Delta(T) = +0.25 dayであった。

検出位置は次のとおり、

     2019 UT             R.A. (2000) Decl.       Mag.
     May  29.57499   21 49 39.57   +11 59 02.4   21.6
          29.58397   21 49 40.14   +11 59 06.1   21.5
          29.59291   21 49 40.70   +11 59 09.6   21.5
          29.60190   21 49 41.27   +11 59 13.2   21.6
     June  1.44032   21 52 43.33   +12 17 55.0   21.0
           1.44551   21 52 43.71   +12 17 56.7   20.8
           1.45070   21 52 44.00   +12 17 58.3   21.1

連結軌道要素と位置推算表は次のとおり、

Orbital elements:
    P/2000 S4 (LINEAR-Spacewatch)
Epoch 2000 Oct. 23.0 TT = JDT 2451840.5
T 2000 Oct. 19.09802 TT                                 MPCW
q   2.2654571            (2000.0)            P               Q
n   0.05184240     Peri.  172.32444     +0.97573820     +0.21441300
a   7.1232685      Node   174.64378     -0.21748396     +0.97250158
e   0.6819638      Incl.   28.32774     -0.02521288     -0.09092711
P  19.01
From 40 observations 2000 Sept. 1-2019 June 1, mean residual 0".5.

    P/2000 S4 (LINEAR-Spacewatch)
Epoch 2019 Oct. 4.0 TT = JDT 2458760.5
T 2019 Sept. 26.88873 TT                                MPCW
q   2.2653510            (2000.0)            P               Q
n   0.05196999     Peri.  173.09660     +0.97549386     +0.21394051
a   7.1116050      Node   173.79232     -0.21767130     +0.97244223
e   0.6814571      Incl.   28.37715     -0.03210833     -0.09265834
P  18.96
From 40 observations 2000 Sept. 1-2019 June 1, mean residual 0".5.

    P/2000 S4 (LINEAR-Spacewatch)
Epoch 2038 Oct. 24.0 TT = JDT 2465720.5
T 2038 Oct.  9.57020 TT                                 MPCW
q   2.2696953            (2000.0)            P               Q
n   0.05188382     Peri.  173.29445     +0.97622994     +0.21056110
a   7.1194767      Node   173.79337     -0.21429668     +0.97320166
e   0.6811991      Incl.   28.37022     -0.03243504     -0.09242590
P  19.00
From 40 observations 2000 Sept. 1-2019 June 1, mean residual 0".5.

    P/2000 S4 (LINEAR-Spacewatch)
Epoch 2019 Apr. 27.0 TT = JDT 2458600.5
T 2019 Sept. 26.85642 TT                                MPCW
q   2.2654386            (2000.0)            P               Q
n   0.05194630     Peri.  173.08266     +0.97545096     +0.21414145
a   7.1137667      Node   173.79483     -0.21786887     +0.97239964
e   0.6815416      Incl.   28.37591     -0.03207135     -0.09264118
P  18.97
From 40 observations 2000 Sept. 1-2019 June 1, mean residual 0".5.

Ephemeris:
    P/2000 S4 (LINEAR-Spacewatch)
Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase   m1
2019 05 03    21 17 31.5 +08 39 36   2.6532  2.6409    78.3    21.9  22.3
...
2019 05 18    21 36 25.2 +10 36 20   2.4282  2.5746    86.6    23.1  22.0
...
2019 05 26    21 45 42.6 +11 34 30   2.3095  2.5411    91.2    23.5  21.9
...
2019 06 01    21 52 15.3 +12 15 04   2.2216  2.5170    94.7    23.7  21.7
2019 06 02    21 53 18.5 +12 21 31   2.2071  2.5131    95.3    23.7  21.7
2019 06 03    21 54 20.9 +12 27 52   2.1926  2.5091    95.9    23.7  21.7
...
2019 06 09    22 00 20.5 +13 03 35   2.1064  2.4862    99.6    23.7  21.6
...
2019 06 17    22 07 37.0 +13 43 45   1.9941  2.4570   104.7    23.6  21.4
...
2019 07 02    22 18 43.9 +14 28 27   1.7940  2.4070   115.0    22.5  21.1

(CBET 4633、MPEC 2019-L11)