Central Bureau for Astronomical Telegrams
IAUC 6035: 1993e
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Circular No. 6035
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)
R. Schulz, T. Encrenaz, J. A. Stuewe and G. Wiedemann communicate:
"We report preliminary results from our study of the impact sites of
fragments A, C, D, E, F, G and H. Near-infrared spectra were
recorded with the IRSPEC spectrometer at the European Southern
Observatory's 3.5-m NTT with a 4".4 slit aligned along the parallel through
the impact sites. On July 17.04 UT the 2.12-micron H2 quadrupole line
was detected with a resolving power of 2000 at the position of fragment
A (about 5 hours after impact) as it moved along the jovian disk.
On July 17.94 H3+ was detected in four transitions around the strong
3.534-micron line with a resolving power of 1700. The region of the
emission appears significantly extended in longitude with respect to
the site of impact C (about 15.5 hours after impact). We continued to
monitor the H3+ multiplet at 3.5 microns during July 18.00-18.10 and
18.83-18.96. No evidence for H3+ emission was found near the E-F
impact region, whereas it was detected at the position of fragments D
(about 14 hours after impact) and G (about 12 hours after impact).
A weak H3+ emission is visible on the leading side of impact region H
(about 15 min after impact), but no H3+ was detected in the region itself.
On July 18.107 we started to monitor the E-F impact region between
2.02 and 2.05 microns. These observations allow the E and F sites to be
distinguished. The spectrum of impact F (about 2 hours after
impact) is characterized by a featureless continuum (which, if thermal,
indicates temperatures of about 1000 K), whereas the already evolved
site E (about 11.5 hours after impact) shows little continuum but
strong H2 S(1) line emission at 2.12 microns. These measurements
suggest that H3+ and H2 are present at more evolved impact sites
rather than shortly after an impact."
N. V. G. Sarma and the observing team at the 10.4-m millimeter-wave
telescope of the Raman Research Institute, Bangalore, report: "We detected
short-duration increases in the jovian continuum flux density at 86 GHz
following several of the impacts. Impact E: 400-percent increase on July
17.637 UT, the upper limit for the duration being 3 min as observations
were made in scanning mode. Impact K: 50-percent increase on July 19.436
for 40 s, followed immediately by a 175-percent increase for about 10 s.
Impact N: increases by 87 percent and 125 percent on July 20.428 and 20.429,
respectively, each lasting about 20 s. Impact P: possible increase by
100 percent on July 20.629 for about 3 s. Impact S: 70-percent increase
on July 21.633 and 60-percent increase on 21.640, each for 30 s. As all
the observations were made under monsoon weather conditions, some of them
may be uncertain. We welcome confirmation from other millimeter-wave
observatories."
1994 July 22 (6035) Brian G. Marsden
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