Central Bureau for Astronomical Telegrams
IAUC 6025: 1993e
The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).
Read IAUC 6026
.dvi or
.ps format.
Circular No. 6025
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)
Further reports received via the SL9 message center include
detections of the impacts on Jupiter of fragments D = 18 and E = 17.
CASPIR 2.34-micron images and IRIS K-grism cubes at Siding Spring
(cf. IAUC 6024) revealed a faint flash due to the D impact on July 17.496 UT
that faded within seconds. A second flash on July 17.500 was about four
times brighter than the C impact site (then on the opposite limb)
and about half as bright as Europa in the K-band, but it faded in less
than 1 min. The K-grism results then revealed a slow brightening
during July 17.512-17.521 and a subsequent decay. CASPIR 3.28- and 3.42-
micron images taken near July 17.514 indicated that the feature was somewhat
brighter at these wavelengths. There was no evidence of the impact in IRIS
H-grism or CASPIR 4.78-micron images.
J. Watanabe and others report the appearance of the plume of fragment
D on July 17.501 UT in 2.36-micron images obtained with the 1.88-m telescope
at the Okayama Astrophysical Observatory. It was fainter than the plume
recorded from the impact of C on July 17.303; that plume was brightest
around July 17.306, and the decay phase was observed over one hour.
The French-Swedish-Spanish Nordic Optical Telescope team (cf. IAUC
6023) reports that the impact of fragment E was recorded at 10 microns
around July 17.637 UT. It was fainter than impact A seen yesterday.
The Calar Alto Observing Team (cf. IAUC 6023) reports the detection
of the fireball from fragment E with the 3.5-m Calar Alto telescope in the
2.3-micron band. The event was first noted on July 17.637 UT, and it
rapidly increased to more than 30 times the brightness of Europa.
By July 17.641 the fireball had dimmed to less than Europa's brightness.
On July 17.768 three spots were visible--a bright one (impact E) just past
the central meridian, a fainter one (impact A) approaching the central
meridian and the faintest one (impact C) just coming over the east limb.
At 2.3 microns the brightest spot was 15-20 times fainter than Io, and
the others were fainter by further factors of about 1.5 and 2.2.
J. Rogers, British Astronomical Association, reports his visual
detection (before sunset using yellow and polaroid filters) with the
0.30-m refractor at the University of Cambridge of conspicuous dark spots
at the predicted impact sites of fragments A and C. Site A, which has
clearly grown since the first Hubble image, was the darker (similar to the
NEB) and remained visible until it approached Jupiter's limb on July
17.851 UT. Site C was on the central meridian on July 17.828 +/- 0.002.
1994 July 17 (6025) Brian G. Marsden
Read IAUC 6026
.dvi or
.ps format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
