Circular No. 6707

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)

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COMET C/1997 O1 (TILBROOK)

A. Beresford informs us that he reported the name of the comet’s discoverer incorrectly (cf. IAUC 6705): it should be Justin Tilbrook. There was also an error in the observed α: for 12^{h}28^{m}.4 read 12^{h}18^{m}.4.

Further precise CCD positions have been reported as follows:

1997 UT α_{2000} δ_{2000} Observer
July 24.37582 12^{h}22^{m}55.^{s}43 −17^{o}16′25′′.2 Garradd
24.37768 12 22 55.68 −17 16 19.4  _{”}
24.37955 12 22 55.93 −17 16 13.9  _{”}
24.47205 12 23 08.67 −17 11 32.7 Abe
24.47899 12 23 09.58 −17 11 10.5  _{”}
24.48247 12 23 09.99 −17 11 00.7  _{”}
24.49269 12 23 11.29 −17 10 20.7 Garradd
24.49353 12 23 11.43 −17 10 19.1  _{”}

G. J. Garradd (Loomerah). 0.25-m f/4.1 reflector. H. Abe (Yatsuka). 0.26-m f/6.0 reflector. Communicated by S. Nakano.

Parabolic orbital elements from 15 observations July 23–24:

T = 1997 July 16.560 TT  ω = 339.^{o}104
Ω = 231.329 }2000.0
q = 1.38550 AU  i = 114.115
1997 TT α_{2000}  δ_{2000}  Δ  r  ϵ  β  m_{1}
July 23 12^{h}19.^{m}72 −18^{o}29.^{′}6 1.302 1.389 72.^{o}4 44.^{o}2 10.0
25 12 24.34 −16 44.4 1.344 1.391 70.7 43.6 10.1
27 12 28.70 −15 06.0 1.386 1.394 69.0 42.9 10.2
29 12 32.84 −13 34.0 1.429 1.397 67.3 42.1 10.2
31 12 36.77 −12 07.9 1.473 1.401 65.6 41.3 10.3
Aug. 2 12 40.53 −10 47.2 1.517 1.406 63.9 40.4 10.4
4 12 44.14 − 9 31.5 1.561 1.411 62.3 39.5 10.5
6 12 47.60 − 8 20.5 1.605 1.417 60.6 38.6 10.5
8 12 50.94 − 7 13.7 1.650 1.424 59.0 37.6 10.6
10 12 54.17 − 6 10.9 1.694 1.431 57.4 36.7 10.7
12 12 57.30 − 5 11.6 1.737 1.438 55.8 35.7 10.8
14 13 00.35 − 4 15.6 1.781 1.446 54.3 34.7 10.9
16 13 03.31 − 3 22.7 1.824 1.455 52.7 33.6 10.9
18 13 06.20 − 2 32.5 1.867 1.464 51.2 32.6 11.0
20 13 09.03 − 1 44.9 1.909 1.473 49.7 31.6 11.1
1997 July 24  \begin{matrix}c \\ ◯ \end{matrix} Copyright 1997 CBAT  Brian G. Marsden