Circular No. 7042

Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION

Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.

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COMET 1998 U4

Timothy B. Spahr, University of Arizona, reports his discovery of a comet. The following observations are available:

1998 UT  α_{2000}  δ_{2000}  m_{1} Observer
Oct. 27.37800 4^{h}08^{m}45.^{s}61 −11^{o}54′13′′.0 17.2 Spahr
27.38600 4 08 45.40 −11 54 17.4  _{”}
27.39420 4 08 45.23 −11 54 21.0  _{”}
28.28339 4 08 25.09 −12 02 00.5  _{”}
28.29100 4 08 24.95 −12 02 03.9  _{”}
28.35567 4 08 23.37 −12 02 37.5 17  _{”}
28.37736 4 08 22.73 −12 02 47.4 17.4 Larsen

T. B. Spahr (Catalina Sky Survey). 0.41-m f/3 Schmidt telescope + CCD.

Tail 30′′ long in p.a. 285^{o}. J. Larsen and J. Scotti (Kitt Peak). 0.9-m Spacewatch Telescope. Coma

diameter 8′′; tail extends 0′.9 in p.a. 288^{o}; m_{2} = 19.1.

COMET C/1998 P1 (WILLIAMS)

Ephemeris extension to IAUC 6991 (elements MPC 32595):

1998/99 α_{2000}  δ_{2000}  Δ  r  ϵ  β  m_{1}
Nov. 13 13^{h}25.^{m}14 −21^{o}35.^{′}0 2.039 1.221 25.^{o}4 20.^{o}3  9.9
18 13 23.97 −20 28.0 2.001 1.250  30.2 23.5 10.0
23 13 22.52 −19 17.8 1.953 1.283  35.4 26.5 10.0
28 13 20.72 −18 03.1 1.896 1.320  40.9 29.3 10.1
Dec. 3 13 18.45 −16 42.1 1.830 1.359  46.7 31.9 10.1
8 13 15.59 −15 12.9 1.757 1.402  52.8 34.0 10.2
13 13 11.99 −13 33.1 1.678 1.447  59.2 35.8 10.2
18 13 07.45 −11 39.7 1.595 1.494  65.9 37.0 10.3
23 13 01.76 − 9 29.2 1.508 1.543  73.1 37.6 10.3
28 12 54.63 − 6 57.2 1.421 1.593  80.8 37.5 10.3
Jan. 2 12 45.75 − 3 59.2 1.334 1.645  89.1 36.7 10.3
7 12 34.75 − 0 30.5 1.253 1.697  98.0 35.0 10.3
12 12 21.20 + 3 32.9 1.179 1.751 107.8 32.3 10.3
17 12 04.70 + 8 11.6 1.117 1.805 118.3 28.7 10.3
22 11 44.90 +13 21.0 1.072 1.860 129.5 24.1 10.3
1998 October 29  \begin{matrix}c \\ ◯ \end{matrix} Copyright 1998 CBAT  Daniel W. E. Green