Circular No. 6984

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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COMETS X/1998 L1 AND X/1998 M7 D. Biesecker, Space Applications Corporation, NASA Goddard Space

Flight Center, reports provisional data (reduced by G. V. Williams) on two more comets found in SOHO-LASCO C3 coronagraphic data. They appear to be Kreutz sungrazers and were also observed by C2. Comet X/1998 L1, mag ∼ 5.5 at its peak, was discovered by S. Stezelberger in the real-time data; the C2 data showed a narrow, faint tail 0^{o}.2 long. Comet X/1998 M7, mag ∼ 5.8 at its peak, was discovered by Biesecker in an automated search of archival data; no tail was evident.

1998 UT  α_{2000}  δ_{2000}
June 10.072  5^{h}10.^{m}7  +18^{o}05′  X/1998 L1
16.406  5 34.2  +20 30  X/1998 M7

COMET C/1998 K5 (LINEAR) Ephemeris extension to IAUC 6962 (elements on MPC 32169):

1998 TT α_{2000} δ_{2000} Δ r ϵ β m_{1}
Aug. 5 3^{h}13.^{m}62 +36^{o}44.^{′}8 0.458 1.016 77.^{o}1 76.^{o}8 12.9
10 3 24.30 +35 00.7 0.490 1.046  79.9 72.6 13.1
15 3 33.01 +33 25.4 0.519 1.082  83.2 68.4 13.4
20 3 39.93 +31 56.6 0.547 1.123  86.8 64.2 13.7
25 3 45.14 +30 32.3 0.571 1.167  90.7 60.0 14.0
30 3 48.69 +29 10.8 0.594 1.216  95.0 55.8 14.2
Sept. 4 3 50.65 +27 50.9 0.615 1.267  99.7 51.7 14.5
9 3 51.06 +26 31.6 0.635 1.320 104.7 47.5 14.7
14 3 49.97 +25 12.0 0.654 1.376 110.1 43.3 15.0
19 3 47.46 +23 51.6 0.673 1.433 115.9 39.1 15.2
24 3 43.63 +22 30.1 0.693 1.491 122.0 34.8 15.4
29 3 38.66 +21 07.7 0.715 1.550 128.3 30.5 15.7
Oct. 4 3 32.74 +19 44.9 0.740 1.610 134.9 26.1 15.9
9 3 26.13 +18 22.5 0.768 1.671 141.7 21.8 16.2
14 3 19.06 +17 01.9 0.800 1.732 148.6 17.5 16.4
19 3 11.80 +15 44.2 0.838 1.793 155.5 13.3 16.7
24 3 04.60 +14 30.8 0.881 1.854 162.4  9.4 16.9

Total visual magnitude estimates: July 25.00 UT, 12.6 (R. J. Bouma, Groningen, The Netherlands, 0.25-m reflector); 29.02, 12.9 (M. Reszelski, Szamotuly, Poland, 0.25-m reflector); Aug. 3.99, 12.9 (Reszelski).

1998 August 5  \begin{matrix}c \\ ◯ \end{matrix} Copyright 1998 CBAT  Brian G. Marsden