Circular No. 6951

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 M3

J. Larsen, Lunar and Planetary Laboratory, has discovered a comet with the 0.9-m Spacewatch telescope. Available CCD astrometry:

1998 UT α_{2000} δ_{2000} m_{1} Observer
May 26.29656 16^{h}43^{m}58.^{s}22 −4^{o}51′11′′.4 18.9 Blythe
26.31430 16 43 57.14 −4 51 03.7 18.9  _{”}
26.33217 16 43 56.01 −4 50 51.7 18.9  _{”}
26.34996 16 43 55.11 −4 50 40.5 18.2  _{”}
26.36755 16 43 54.13 −4 50 31.8 18.2  _{”}
June 24.26372 16 17 45.24 −1 00 30.6 17.6 Larsen
24.28486 16 17 44.16 −1 00 22.5 17.4  _{”}
24.30618 16 17 43.14 −1 00 13.7 17.6  _{”}
24.32783 16 17 41.96 −1 00 02.9 18.0  _{”}
24.33236 16 17 41.73 −1 00 02.2 17.8  _{”}
24.33629 16 17 41.55 −1 00 00.1 17.8  _{”}
25.14598 16 17 01.84 −0 54 36.8 17.6 Offutt
25.15299 16 17 01.47 −0 54 33.9 17.6  _{”}
25.15880 16 17 01.19 −0 54 31.5 17.8  _{”}
25.16480 16 17 00.90 −0 54 29.7 18.1  _{”}

M. Blythe, F. Shelly and M. Bezpalko (Socorro). 1-m f/2.15 reflector. Measurers J. Stuart and H. Viggh. Prediscovery observations identified by the undersigned in LINEAR data.

J. Larsen (Kitt Peak). Tail 0′.12 long in p.a. 323^{o}. W. Offutt (Cloudcroft). 0.6-m f/7 Ritchey-Chrétien. Coma 20′′ in diame-

ter, densest toward p.a. 330^{o}. No tail seen in 200-s exposures. Parabolic orbital elements from 14 of the above observations:

T = 1998 June 28.680 TT  ω = 18.^{o}978
Ω = 255.513 }2000.0
q = 5.77004 AU  i = 113.387
1998TT α_{2000}  δ_{2000}  Δ  r  ϵ  β  m_{1}
June 21 16^{h}20.^{m}49 − 1^{o}22.^{′}9 4.885 5.770 147.^{o}7 5.^{o}4 17.6
26 16 16.34 − 0 49.0 4.928 5.770 142.8 6.1 17.6
July 1 16 12.41 − 0 17.6 4.978 5.770 137.7 6.8 17.6
6 16 08.75 + 0 11.2 5.034 5.770 132.5 7.5 17.6
11 16 05.37 + 0 37.5 5.097 5.771 127.3 8.1 17.6
16 16 02.30 + 1 01.3 5.165 5.771 122.2 8.6 17.7
1998 June 25  \begin{matrix}c \\ ◯ \end{matrix} Copyright 1998 CBAT  Brian G. Marsden