--------- Subj: Non-detection of Fragment B We are observing at Palomar with the 200-inch Hale telescope, using a 7.9 micron imaging spectrometer in imaging mode and a 256x256 InSb at 2.35 microns. We began observing with the imaging spectrometer at around 02:35 UT and with the InSb camera at around 03:05 UT. We have not seen anything as of 03:55 UT. --------------- Subj: Negative observations of B impact from ESO La Silla Continuing observations with TIMMI at 9um on the 3.5m telescope and IRAC 2B at 2.2um on the 2.2m at ESO La Silla show that nothing was seen over the predicted impact site B up to 3:35UT, 17 July. Conditions were not ideal but this is a strong indication of differences between the A and B impacts. Richard West & Richard Hook, ESO Garching --------------- Subj: Nondetection of B impact We obtained a sequence of images every 10 seconds from 2:44 to about 3:25 UT, of Jupiter at 1.7 microns (till 3:12) and 2.3 microns (thereafter), and saw nothing unusual at all on Jupiter's limb. Predicted impact time was 2:54. Clouds rolled in after 3:25. John Spencer, Darren DePoy, OSIRIS, CTIO 4-meter. --------------- Subj: Persistance of A and Lack of B Observations using a NICMOS2 array and a NICMOS3 spectrometer were obtained at approx. 0hr U.T. of the A impact site which was clearly visible at 2.2um. A spectrum of the impact site from 2.0-2.4um at R=1600 was obtained with the impact site clearly distinguishable from the remainder of the impact latitude. Observations from 02:40 U.T. through 03:30 U.T. showed nothing from the B impact site in either 2um images or spectroscopically. In other data we have acquired after the A impact but before B we observed the H2 auroral emission to be much weaker than in March at the same system III longitude. George and Marcia Rieke, Milagros Ruiz, Chad Engebracht, Pat Frawley, Dave Wittman Steward Observatory 90-inch, Kitt Peak --------------- Subj: No B Detection We observed Jupiter from 02:35 to 4:02 UT with 2 narrow band filters centered at 2.22 and 2.36 microns with a 1 - 2.5 imaging camera on the Apache Point Observatory 3.5 m telescope. We see no evidence of any consequence of the B impact. This instrument is the second generation of the SPIREX camera at the South Pole which reported a positive detection of A in the same filter. Nancy Chanover Mark Marley New Mexico State -------------- Subj: Detection of B plume at 3 micron Report from W. M. Keck Observatory, Mauna Kea, Hawaii: Impact B. We observed impact B in a narrow band L band (3.27-3.44 micron); the plume was faint, but clearly detected at the expected position, starting at 02:56, fading at around 3:13. Imke de Pater, James Graham, Garrett Jernigan and collaborators. -------------------- Monitoring the H3+ ionospheric lines at 3.5 microns with CGS4 echelle spectrometer on UKIRT, Mauna Kea, Hawaii, we saw a fivefold brightening of the emission around the time of impact of fragment B (around 2:50 UT) on the east limb of Jupiter. The spectrometer slit was approximately aligned on the nominal impact latitude. This faded over 90 minutes. Steve Miller Mary-Frances Jagod Tom Geballe Tim Brooke ---------- Subj: IRTF detection of C fragment impact site Beginning at 1994 Jul 17 7:15 UT, the NASA/Infrared Telescope Facility observed the development of a bright spot on Jupiter associated with the impact of fragment C. The NSFCAM near-infrared camera took 0.9-sec integrations every 3.6 seconds at a wavelength of 2.248 +/- 0.011 microns. Starting at 6:51 UT, the camera recorded Io and Europa, searching for a flash; no flash was obvious but the data are yet to be photometrically reduced. At 7:15 the telescope moved to Jupiter, and detected both the remnant of the A impact, with a surface brightness similar to that of the south polar hood at this wavelength, and a dim spot from fragment C. By 7:18, site C was considerably brighter than site A, but by 7:28 site C had faded to about site A's brightness, and continued to fade until about 7:40, when it was considerably fainter. NASA/IRTF Comet Collision Science Team ------------ Subj: SPIREX detects fragment C impact site SPIREX detected a fragment C impact site at 07:19 UT at a wavelength of 2.36 microns. The impact site has also been monitored at 2.20 microns. SPIREX will continue to monitor further impacts in these bands. Mark Hereld, Hien Nguyen, Bernard J. Rauscher, Scott A. Severson Astronomy & Astrophysics Center, University of Chicago ------------- Subj: Detection of HCN following impact C 16th July Detection of HCN 4-3 in emission following impact of fragment C: --------------------------------------------------------------- We observed the HCN 4-3 line at 354.505 GHz using Receiver B3i on the JCMT with a beamwidth of 14" FWHM. We tracked on the position of fragment B for over 1 hour, but did not detect anything to an rms noise of 0.2 K antenna temperature. Observations of the location of the fragment C impact point over a 30-minute period as it rotated into view produced a detection of an approx. 1-K line at the correct velocity (19 km/s). The line half-width is about 10 km/s. Subsequent observations did not result in a confirmation of the detection, but Jupiter was setting and the system temperature rapidly increasing. We are therefore not able to say whether or not the effect was short-lived. Matt Griffin, Andre Marten, David Naylor, Gary Davis, Greg Tompkins --------------------- Subj: UKIRT/CGS4 observations of the impact of fragment C CGS4 (with echelle at about 20 km/s resolution) on UKIRT detected dramatic changes in the spectrum near 3.5um at the location where the C fragment struck Jupiter. In addition to a bright continuum (where there previously was essentially none), the relative strengths of pre-existing emission lines of H3+ changed and many new lines appeared, very few of which are identified by us at present. In particular, at the wavelength of a previously undetectable "hot band" transition of H3+, a bright line appeared whose strength surpassed that of all other pre-existing H3+ lines. A second line, unidentified at present, succeeded in saturating its central pixel in a ten second exposure. Some of the lines seem considerably (Doppler) broadened, but, due to the high density of spectral features, confirmation will have to wait until after the observers get some sleep. The emission faded with a 1/e time of roughly 15 minutes. Tom Geballe Mary-Frances Jagod Steve Miller Tim Brooke ------------------ Subj: Japanese Observation of C & D First report from Okayama Astrophysical Observatory. We observed the plumes of C and D with Near-IR camera attached to 188cm telescope at Okayama Astrophysical Observatory, National Astronomical Observatory of Japan. Thermal plume of C appeared 07:17 UT on July 17 on 2.36 micron images. It was the brightest around 07:21. The decay phase was observed over one hour. Thermal plume of D appeared 12:01 UT on July 17, but it is fainter than that of C. J. Watanabe, T. Yamashita, H. Hasegawa, S. Takeuchi, M. Abe, Y. Hirota, E. Nishihara, A. Mori, S. Okumura, --------------- Subj: Fragment D - No flash CCD imaging at Perth observatory of Io, Europa, and the limb of Jupiter with a duty cycle of only about 30% did not reveal any obvious flashes associated with the impact of fragment D. Photometric analysis will be required to remove large scintillation effects. Mike A'Hearn ------------- First report from Okayama Astrophysical Observatory. We observed the plumes of C and D with Near-IR camera attached to 188cm telescope at Okayama Astrophysical Observatory, National Astronomical Observatory of Japan. Thermal plume of C appeared 07:17 UT on July 17 on 2.36 micron images. It was the brightest around 07:21. The decay phase was observed over one hour. Thermal plume of D appeared 12:01 UT on July 17, but it is fainter than that of C. J. Watanabe, T. Yamashita, H. Hasegawa, S. Takeuchi, M. Abe, Y. Hirota, E. Nishihara, A. Mori, S. Okumura, ----------- Subj: Impact e seen at 10 microns with CAMIRAS at NOT Impact E has been seen at 10 microns with the CAMIRAS camera mounted on the Nordic Optical telescope at about 15h17min . UT. It was fainter than impact A seen yesterday. French-Swedish-Spanish team ----------------- Calar Alto reports the detection of the fireball from fragment E with the 3.5m telescope at the 2.3 um band. The event was first noted at 15:17:30 and rapidly increased to more than 30 times the brightness of Europa. By 15:23, the fireball has dimmed to less than Europa's brightness. The Calor Alto Observing Team Max Planck Institut fuer Astronomie (Heidelberg, Germany) Tom Herbst Kurt Birkle Ulrich Thiele Max Planck Institut fuer Kernphysik (Heidelberg, Germany) Doug Hamilton Universitaets-Sternwarte Muenchen (Muenchen, Germany) Hermann Boehnhardt Alex Fiedler Karl-Heinz Mantel Instituto de Astrofisica de Andalucia (CSIC Granada, Spain) Jose Luis Ortiz Astrophysical Institute Arcetri (Florence, Italy) Giovanni Calamai Andrea Rickicki ----------------- Subj: Fragment E - No Optical Flashes Fragment E (predicted at 1505 UT) CCD imaging at Perth Observatory July 17 1450-1530 UT. Broad CH4 filter at 893nm, 2-sec exposures of limb of Jupiter (rest of Jupiter occulted by mask) with 60-70% duty cycle. No flashes or plumes were obvious in the raw data. Flashes greater than 25% of a square arcsec of Jupiter should have been seen in the raw data. Mike A'Hearn