Central Bureau for Astronomical Telegrams
IAUC 6032: 1993e
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Circular No. 6032
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 SHOEMAKER-LEVY 9 (1993e)
SL9 message-center reports note that at the Keck Observatory
I. de Pater et al. confirmed the impact of "lost fragment M = 10"
(cf. IAUC 6030) around July 20.256 UT, the impact site being clearly
separated from that of K, which came into view a little later. Negative
reports of K-band observations near the expected time of the P = 8 impact
were received from the South African Astronomical Observatory (two groups),
the Teide Observatory and Pic du Midi. The Pic du Midi team reported
a very short, tiny flash in the K band on July 20.822 that may have
been due to fragment Q2 = 7b, followed by a double flash from Q1 = 7a
on 20.842 and 20.847, the latter being the more prominent. Plume
phenomena were observed at the Calar Alto Observatory around the impact
times of the Q2 and Q1 fragments; two spot-like features appeared over the
impact limb of Jupiter around July 20.822 and 20.847, the latter
considerably brighter than the former, and they were simultaneously
identified by direct imaging at 2.3 and 1.7 microns and by fast photometry
in the 3.1-micron range. A further spot appeared over the limb around
July 20.842, and at 2.3 microns it was intermediate in brightness
between the others. At the Teide Observatory the Q2 plume was noted
on July 20.828 (evidently with the IAC-80 telescope at 750, 892 and 948 nm);
the impact of Q1 was difficult to separate from the Q2 plume, but it was
clearly observed at 892 nm by July 20.851, the impact cloud later being
clearly double. The Q2 impact did not show in the raw 2.166-micron data from
the Carlos Sanchez telescope, but the Q1 flare appeared on July 20.847.
The impact of fragment R = 6 was detected at 2.34 microns using CASPIR
on the Australian National University (not Observatory, as was stated
on IAUC 6030) 2.3-m telescope at Siding Spring; distinct brightening
began on July 21.237 UT and continued until the detector saturated on
21.238; bright emission at the impact site was detected at 4.78 microns
on 21.242 but had faded by 21.256. P. Nicholson and others using the
5-m reflector at Palomar first noted the R flare at 3.6 and 5 microns
on July 21.233; rapid brightening occurred on 21.237, reaching a peak
on 21.240, when diffraction spikes were observed at 5 microns. The 5-micron
flux dimmed by a factor of 40 by 21.243, and the image was observed
to be extended about 2" along the limb on 21.246; by 21.249 the 5-micron
flux had dropped to the level of the first images, and by 21.258 it was
comparable to that of the planet. At Table Mountain Observatory
(Wrightwood, CA) J. Young and others remarked on the appearance (at 890
nm) of the R impact site on Jupiter's disk on July 21.258, followed by
the Q impact site on 21.274.
1994 July 21 (6032) Brian G. Marsden
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