Circular No. 6919

Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION

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COMET P/1998 K4 (MUELLER 3) J. V. Scotti, Lunar and Planetary Laboratory, reports his recovery of

comet P/1990 S1 (= 1990l = 1990 XIII) with the Spacewatch telescope on Kitt Peak. The comet is very slightly diffuse, with a coma diameter of 12′′ on May 26.45 UT. The indicated correction to the prediction by S. Nakano on MPC 27081 is ΔT = −0.7 day.

1998 UT  α_{2000}  δ_{2000}  m_{2}
May 24.43002  21^{h}31^{m}51.^{s}97  −11^{o}59′36′′.1  20.6
24.44144  21 31 52.30  −11 59 34.0  21.4
24.45263  21 31 52.66  −11 59 33.5  21.1
26.44283  21 32 53.34  −11 56 56.4  21.2
26.45382  21 32 53.76  −11 56 55.5  21.2
26.47267  21 32 54.27  −11 56 54.6  21.0

The following improved orbital elements, by the undersigned, satisfy 24 observations 1990–1998 with mean residual 1′′.0:

Epoch = 1999 Mar. 3.0 TT

T = 1999 Mar. 20.5047 TT  ω = 225.^{o}4492
e = 0.288718  Ω = 137.9665 }2000.0
q = 3.010484 AU  i = 9.4137

a = 4.232474 AU n^{o} = 0.1131912 P = 8.707 years

1998 TT α_{2000} δ_{2000} Δ r ϵ β m_{2}
May 17 21^{h}27.^{m}57 −12^{o}12.^{′}1 3.147 3.397 95.^{o}6 17.^{o}2 21.1
27 21 33.16 −11 56.2 2.987 3.376 103.8 16.9 20.9
June 6 21 37.23 −11 49.1 2.834 3.354 112.4 16.2 20.8
16 21 39.64 −11 52.2 2.689 3.333 121.4 15.1 20.6
26 21 40.28 −12 06.6 2.557 3.313 130.9 13.4 20.4
July 6 21 39.09 −12 32.8 2.441 3.293 140.9 11.2 20.2
16 21 36.15 −13 10.4 2.345 3.273 151.3  8.6 20.0
26 21 31.67 −13 57.7 2.273 3.254 162.1  5.5 19.8
Aug. 5 21 26.07 −14 51.7 2.226 3.236 173.2  2.1 19.5
15 21 19.93 −15 48.5 2.207 3.218 175.5  1.4 19.4
25 21 13.91 −16 43.7 2.216 3.200 164.2  4.9 19.7
Sept. 4 21 08.74 −17 33.3 2.251 3.184 153.1  8.2 19.8
14 21 04.99 −18 14.4 2.311 3.167 142.3 11.2 20.0
24 21 03.09 −18 44.9 2.392 3.152 132.0 13.7 20.2
Oct. 4 21 03.28 −19 04.1 2.489 3.137 122.1 15.7 20.3
1998 May 26  \begin{matrix}c \\ ◯ \end{matrix} Copyright 1998 CBAT  Brian G. Marsden