------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 864 1994 July 24 09.35UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England. Telephone/FAX(0256)471074 Int:+44256471074 INTERNET: GMH at AST.STAR.RL.AC.UK or GMH at GXVG.AST.CAM.AC.UK ------------------------------------------------------------------- PERIODIC COMET SHOEMAKER-LEVY 9 (1993e)/COLLISION WITH JUPITER Fragment P 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. Fragments Q1 and Q2 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. IAUC 6032 Fragment R The impact of fragment R = 6 was detected at 2.34 microns using CASPIR on the Australian National University 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. IAUC 6032 Fragment S The South African Astronomical Observatory reports via the SL9 message center that J. Shykula used the 1.9-m telescope for high-speed K-band photometry of the impact of fragment S = 5. Definite brightening began around July 21.640 UT, with peak brightness around 21.645 and a return to relatively constant signal levels by 21.651; peak brightness was nearly twice that seen for impact Q, with a peak K mag about 1.19. Using the 0.75-m telescope and PtSi camera K. Sekiguchi obtained images of Jupiter at 30-s intervals during the impact. A low-level brightening began around July 21.636 and began to fade before a much more dramatic brightening began around 21.640. Peak brightness occurred around 21.645, and by 21.653 there was definitely no remaining obvious excess brightness from this impact. The bright spot at the impact site could not easily be separated from those for impacts R, G and D. The S impact plume was considerably brighter than that seen for fragment H. Guy M Hurst --- 00028 --- Date: Sun, 24 Jul 94 20:44:15 +0100