Circular No. 6834

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)

S/1997 U 2

Following up IAUC 6833, computations by B. G. Marsden, G. V. Williams, and also K. Aksnes, show that the orbit from the 1997 observations alone is sufficiently indeterminate that there is no a priori knowledge of the number N of revolutions made by the satellite between 1984 and 1997. Nevertheless, the extensive series of data by W. B. Offutt, in particular, renders it rather likely that N = 6, the residuals from solutions with N = 5 or 7 yielding small, but definite, systematic trends in the residuals.

Epoch = 1998 July 6.0 TT

T = 1999 June 30.0377 TT  ω = 340.^{o}9973
e = 0.344510  Ω = 244.5561 }2000.0
q = 0.038760 AU  i = 154.5251

a = 0.059132 AU n^{o} = 0.452927 P = 795 days

1998 TT α_{2000} δ_{2000} Δ r_{U} ϵ Δα′′ Δδ′′
Mar. 8 20^{h}54.^{m}31 −18^{o}00.^{′}8 20.578 0.077 36.^{o}3 312+ 298+
18 20 56.27 −17 53.2 20.470 0.078 45.8 351+ 301+
28 20 58.01 −17 46.4 20.343 0.078 55.3 389+ 303+
Apr. 7 20 59.49 −17 40.8 20.199 0.079 64.8 426+ 304+
17 21 00.68 −17 36.3 20.045 0.079 74.3 461+ 305+
27 21 01.57 −17 33.2 19.882 0.079 83.8 496+ 304+
May 7 21 02.12 −17 31.4 19.717 0.079 93.4 529+ 302+
17 21 02.35 −17 31.0 19.553 0.079 103.0 561+ 299+
27 21 02.24 −17 32.1 19.396 0.080 112.6 591+ 295+
June 6 21 01.81 −17 34.5 19.251 0.079 122.3 619+ 289+
16 21 01.08 −17 38.2 19.120 0.079 132.1 644+ 281+
26 21 00.08 −17 42.9 19.010 0.079 141.9 668+ 272+
July 6 20 58.85 −17 48.6 18.922 0.079 151.7 689+ 262+
16 20 57.44 −17 54.9 18.860 0.079 161.6 707+ 250+
26 20 55.90 −18 01.6 18.826 0.078 171.5 723+ 237+
Aug. 5 20 54.31 −18 08.5 18.821 0.078 178.4 736+ 223+
15 20 52.72 −18 15.2 18.846 0.077 168.5 746+ 208+
25 20 51.20 −18 21.5 18.900 0.077 158.5 754+ 193+
Sept. 4 20 49.82 −18 27.1 18.981 0.076 148.5 758+ 177+
14 20 48.63 −18 31.9 19.088 0.075 138.5 760+ 161+
24 20 47.69 −18 35.7 19.217 0.075 128.5 759+ 144+
Oct. 4 20 47.03 −18 38.2 19.364 0.074 118.5 756+ 128+
14 20 46.68 −18 39.5 19.526 0.073 108.6 750+ 112+
24 20 46.68 −18 39.5 19.697 0.072 98.6 741+ 96+
1998 March 7  \begin{matrix}c \\ ◯ \end{matrix} Copyright 1998 CBAT  Brian G. Marsden