Circular No. 6988

Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION

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

IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)

     URL http://cfa-www.harvard.edu/iau/cbat.html

Phone 617-495-7244/7440/7444 (for emergency use only)

COMET C/1998 P1 (WILLIAMS)

The following precise CCD positions have been reported:

1998 UT α_{2000} δ_{2000} m_{1} Observer
Aug. 11.43374 15^{h}01^{m}41.^{s}90 −63^{o}50′25′′.5 13.8 Lee
11.44783 15 01 34.38 −63 49 24.7 16.0  _{”}
11.44887 15 01 33.81 −63 49 20.6 13.5  _{”}
11.44962 15 01 33.42 −63 49 17.9 13.5  _{”}
11.46033 15 01 27.66 −63 48 31.4 13.5  _{”}
11.46241 15 01 26.50 −63 48 22.4 13.3  _{”}
12.00766 14 56 46.01 −63 09 46.9  Mendez
12.01497 14 56 42.29 −63 09 15.9  _{”}
12.03809 14 56 30.78 −63 07 37.1  _{”}
12.04598 14 56 26.71 −63 07 03.0  _{”}
12.06699 14 56 16.20 −63 05 33.0  _{”}
12.37075 14 53 49.76 −62 44 09.7 13.6 Lee
12.37214 14 53 49.12 −62 44 03.8 13.5  _{”}
12.40512 14 53 33.27 −62 41 43.9 13.3  _{”}
12.40616 14 53 32.80 −62 41 39.1 13.4  _{”}

S. Lee (Rainbow Observatory, nr. Coonabarabran). 0.20-m f/4.5 reflector. O. Mendez and J. Scheck (Los Molinos). 0.35-m f/6.4 reflector.

Parabolic orbital elements from 25 observations Aug. 11–12:

T = 1998 Oct. 16.95 TT  ω = 292.^{o}81
Ω = 156.09 }2000.0
q = 1.1623 AU  i = 145.62
1998 TT α_{2000}  δ_{2000}  Δ  r  ϵ  β  m_{1}
Aug. 10 15^{h}15.^{m}71 −65^{o}31.^{′}9 0.977 1.568 103.^{o}9 38.^{o}9 9.4
15 14 35.94 −59 42.0 1.053 1.520  94.7 41.6 9.4
20 14 13.45 −54 23.7 1.142 1.473  86.0 43.3 9.5
25 13 59.76 −49 50.7 1.239 1.428  78.1 43.9 9.5
30 13 50.91 −46 00.8 1.339 1.385  70.7 43.5 9.5
Sept. 4 13 44.94 −42 47.5 1.440 1.345  63.8 42.3 9.6
9 13 40.79 −40 04.0 1.539 1.308  57.4 40.4 9.6
14 13 37.81 −37 44.3 1.634 1.274  51.2 38.0 9.6
19 13 35.64 −35 43.4 1.723 1.244  45.4 35.1 9.6
24 13 34.02 −33 57.6 1.805 1.218  39.9 31.9 9.6
29 13 32.77 −32 23.5 1.879 1.197  34.6 28.3 9.7
Oct. 4 13 31.78 −30 58.7 1.943 1.181  29.5 24.7 9.7
1998 August 12  \begin{matrix}c \\ ◯ \end{matrix} Copyright 1998 CBAT  Brian G. Marsden