Central Bureau for Astronomical Telegrams
IAUC 6027: 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 6028
.dvi or
.ps format.
Circular No. 6027
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)
P. D. Feldman, Johns Hopkins University, reports for the HST observing
team the results of further analysis of FOS spectra of a region near
fragment G = 15 taken on July 14: "The first two-minute segment of a
26-min exposure beginning July 14.556 UT shows strong emission of the
Mg II 280-nm doublet that is not detectable in any other FOS segment
(total observation time 60 min). This emission was mistakenly attributed
to detector noise in the initial report of a null result (IAUC 6021).
No other spectral feature is detected in the same segment. The doublet
is resolved, indicating a localized source of emission in the
1".22 x 3".66 aperture, and the average brightness in the aperture is
140 Rayleighs. A threefold brightening of the continuum commences
approximately 18 min after the appearance of Mg II and is characterized by
a reddening of the spectrum. The duration of this enhancement
is less than 20 min. At the time of the observation, the fragment was
3.8 x 10**6 km from Jupiter and may have crossed the Jovian magnetopause."
Reports received via the SL9 message center describe the spectacular
detection of the impact of fragment H = 14. SPIREX (cf. IAUC 6026)
imaged the impact site over the limb on July 18.818 UT at 2.36 and 2.22
microns; the peak brightness appeared to be smaller than that of the G
impact but still significantly larger than all other previous impacts.
The Calar Alto Observing Team (cf. IAUC 6023) detected the initial
brightening of the H impact on July 18.813 with a 2.3-micron
filter on the 3.5-m telescope and a 3.1-micron filter on the 2.2 m
telescope; the spot increased to a maximum brightness over about 10 min,
and impact sites D and G were still visible to the west of the H plume.
K. Sekiguchi detected the H plume on July 18.814 with the South African
Astronomical Observatory's 0.75-m telescope and PtSi infrared camera at
2.2 microns; the plume became considerably brighter than that observed at
the impact of fragment E and faded in about 20 min. R. M. West reports
that at the European Southern Observatory the H impact was first detected
at 9.1-10.4 microns (3.6-m reflector + TIMMI; cf. IAUC 6026) on July
18.815, with the intensity of the plume at 10 microns about 50 times
that of the entire disk of Jupiter on July 18.823; it was seen
without subtraction of the sky signal, indicating a temperature in
excess of 300 K.
J. Lancashire, British Astronomical Association, reports his visual
observation with the 0.20-m refractor at the University
of Cambridge Observatories of the central part of impact site H
crossing Jupiter's central meridian on July 18.926 +/- 0.003 UT, close
to the prediction on IAUC 6026.
1994 July 18 (6027) Brian G. Marsden
Read IAUC 6028
.dvi or
.ps format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
