Circular No. 7502

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)

CBAT@CFA.HARVARD.EDU (science)

URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304

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

COMET P/2000 S4

T. Gehrels reports his discovery of a faint comet on Oct. 2 images taken with the Spacewatch telescope at Kitt Peak, noting it to have a 4′′ tail in p.a. 170^{o}. T. B. Spahr, Minor Planet Center, linked it to an asteroidal object observed on Sept. 23 and 26 reported earlier by LINEAR and then found LINEAR observations made on Sept. 1. At the request of Gehrels, P. Massey obtained images of the object in subarcsecond seeing with the 4-m Mayall Telescope at Kitt Peak on Oct. 3.25 UT, showing the comet to have a fan-shaped structure 4′′ long spanning p.a. 0^{o}–80^{o}. Available astrometry:

2000 UT α_{2000} δ_{2000} m_{2} Observer
Sept. 1.19481 21^{h}26^{m}52.^{s}70 +6^{o}27′38′′.3 19.0 LINEAR
1.20801 21 26 52.56 +6 27 21.1 19.4  _{”}
1.22118 21 26 52.42 +6 27 06.5 19.5  _{”}
1.23439 21 26 52.24 +6 26 50.8 19.5  _{”}
1.24758 21 26 52.01 +6 26 34.6 19.6  _{”}
23.19398 21 27 29.17 −1 01 08.4 19.6  _{”}
23.20892 21 27 29.36 −1 01 24.5 20.0  _{”}
23.22341 21 27 29.59 −1 01 43.8 20.0  _{”}
23.23814 21 27 29.74 −1 01 59.9 19.3  _{”}
26.09867 21 28 24.27 −1 57 57.5 18.9  _{”}
26.11347 21 28 24.51 −1 58 13.3 19.7  _{”}
26.12822 21 28 24.95 −1 58 29.1 19.9  _{”}
26.14362 21 28 25.13 −1 58 47.7 19.7  _{”}
Oct. 2.15363 21 31 00.80 −3 50 58.1 20.5 Gehrels
2.17455 21 31 01.40 −3 51 21.5 21.1  _{”}
2.19557 21 31 02.00 −3 51 43.6 20.2  _{”}
3.16027 21 31 32.33 −4 08 56.8 19.8  _{”}
3.16492 21 31 32.56 −4 09 01.1 19.9  _{”}
3.17061 21 31 32.69 −4 09 07.4 20.3  _{”}
3.30748 21 31 36.86 −4 11 32.0 19.7  _{”}
3.31192 21 31 36.99 −4 11 37.9 19.6  _{”}
3.31642 21 31 37.17 −4 11 41.6 19.8  _{”}

Orbital elements from the above observations:

T = 2000 Oct. 19.2225 TT  ω = 172.^{o}3746
e = 0.682838  Ω = 174.6363 }2000.0
q = 2.265755 AU  i = 28.3383

a = 7.143832 AU n^{o} = 0.0516187 P = 19.094 years

2000 October 3  \begin{matrix}c \\ ◯ \end{matrix} Copyright 2000 CBAT  Daniel W. E. Green