Central Bureau for Astronomical Telegrams
IAUC 5671: 1992t
The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).
Read IAUC 5672
.dvi or
.ps format.
Circular No. 5671
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
PERIODIC COMET SWIFT-TUTTLE (1992t)
Further to IAUC 5670, Waddington, considering several assumed
values of A2 between -0.0075 and +0.0075, has independently shown that
A2 = -0.0025 yields T = +188 Aug. 17 and -68 July 15; although the
computation for -68 is heavily influenced by a close approach to the
earth in +188, this solution is significant in that it yields no
other approaches within 0.5 AU of the earth between +188 and 1737.
The general stability of Waddington's result is confirmed by G. V.
Williams (Harvard-Smithsonian Center for Astrophysics = CfA), who
finds that the actual orbit and similar nongravitational parameters
on IAUC 5670 yield T = +188 July 20 and an earth approach
to 0.23 AU 12 days later; with an arbitrary change of up to -20 days in
T a closer approach and a representation of the -68 observations becomes
possible. J. E. Chambers (Manchester University and CfA) finds the
comet's long-term motion to be dominated by the 1:11 mean-motion
resonance with Jupiter, in spite of the nongravitational effects and
occasional encounters with the earth and Saturn. Although post-perihelion
observations in 1993 and subsequently should be examined for a possible
repetition of the systematic residuals of 1862 Oct., the proposed
identity with the +188 comet suggests that the next two returns of
P/Swift-Tuttle will likely be within a day of T = 2126 July 11 and 2261
Aug. 12 and that there is very little possibility of the comet's
collision with the earth during the next millennium.
1992/93 R. A. (2000) Decl. Delta r Elong. Phase m1
Dec. 4 19 09.67 + 0 51.3 1.428 0.969 42.6 43.5 5.1
6 19 15.08 - 1 08.7 1.462 0.964 40.9 42.0 5.1
8 19 20.25 - 3 03.2 1.496 0.961 39.2 40.4 5.1
10 19 25.20 - 4 52.6 1.530 0.959 37.5 38.7 5.2
12 19 29.95 - 6 37.2 1.565 0.958 35.8 36.9 5.2
14 19 34.51 - 8 17.1 1.600 0.959 34.1 35.1 5.2
16 19 38.91 - 9 52.6 1.634 0.960 32.4 33.3 5.3
18 19 43.17 -11 24.1 1.668 0.963 30.7 31.4 5.4
Feb. 12 21 24.70 -39 17.4 2.221 1.400 25.9 17.9 8.4
17 21 34.65 -41 13.0 2.229 1.457 29.8 19.7 8.7
22 21 45.06 -43 08.6 2.233 1.515 33.9 21.3 9.0
27 21 56.01 -45 04.7 2.233 1.574 37.9 22.8 9.2
Mar. 4 22 07.58 -47 02.1 2.229 1.634 42.0 24.0 9.4
1992 December 5 (5671) Brian G. Marsden
Read IAUC 5672
.dvi or
.ps format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
