Wieder drei Einschlaege - mehr Ueberraschungen: Report Nr.9, 18.7., 2:00 CST ---------------------------------------------------------------------------- Die interessanteste Entwicklung ist vielleicht, dass eine Reihe Amateurastro- nomen mit nicht unbedingt gewaltigen Teleskopen die dunklen Spuren des Impakts A gesehen und/oder photographiert haben: Was das HST sah, scheint durchaus auch irdischen Betrachtern zugaenglich zu sein. Nur A+C haben allerdings einen eindeutigen dunklen Fleck bewirkt, die anderen Impakte sind praktisch nur im Nahen Infrarot, aber doch bitteschoen jenseits von 2 Mikrometern, eindrucks- volle Erscheinungen. Hier z.B., was in sci.astro zu lesen war: From: GREG BOCK Subject: amateur visual obs. of sl9 impact remnants? Date: Mon, 18 Jul 1994 01:29:14 GMT During the period approx. 08:30 UT, and 11:00 UT, I observed Jupiter with a 300cm Newtonian located at Surfer's Paradise, Queensland, Australia. A second 350mm Newt. was also set up alongside. Both observed at around 200X. We observed two features we suspect were the remains of the A and C impact sites. The suspected A impact site appeared as a dark cresent shaped object following the GRS and the suspected C impact site was visible as a dark spot just off the following limb of the planet at approx.08:45 UT. This changed shape as Jupiter turned, so that it became elongated as time passed. Seeing conditions were excellent until approx 11:00 UT, at which time the suspected c impact site was more difficult to make out. Due to the degrading seeing, it is not possible to say when it disappeared from the preceding limb. My question is:...has anyone else observed these features and can confirm them for me? Thanks, Greg Bock, Southern Astronomical Society, Queensland, Aust. From: Dan Bruton Subject: Re: Dark feature on Jupiter at 7/17/1994 2:53 UT Date: 17 Jul 1994 22:23 CDT This could be impact site of E or F...not sure. It is clearly visible in a 14" (f/11) Schmidt Cassegrain Telescope. It is quite dark...like a moon shadow but it is definitely not a shadow. The dark spot will transit the central meridian about 1 hour after the time given above. The latitude of the feature is about 45 degrees south...just south of a naturally occurring white spot. And there is another feature on the limb just now rotating into view! This one could be the impact site of A. It is not quite so dark as the other spot. They are roughly the size of white spots BC and DE of the south temperate belt. The features were also seen in a 11.5" Newtonian. Wow! . ' |||||||||||||||||||| . || Dan Bruton || . . . || Texas A & M || `. . || astro@tamu.edu || `. ` : : ` |||||||||||||||||||| . . Und im UMD-Computer, Abteilung Early Reports, war heute zu lesen: Steve Lucas relays the following report: ...From J.Beish \(Mars observer/A.L.P.O. Recorder\): "....Second impact result sighted at 0315 UT, 17 July 94 and verified at 0335UT as small elongated dot, dark, no color estimates. Dot approx. 30 degrees from following limb in SSTZ and maybe touching SSTB. Not as large as first hit \(A\), but it has not had development time. The first hit appeared to have affected STB, slightly, and SSTB more so, like a wave action. It seems that the SSTB was either being taken in by the first hit low pressure, or cyclonic type appearing feature. Also, the SSTB appeared to be moving slightly north in a wave action...." This observation was further confirmed by S. Coe \(AZ\), and A.J. Crayon \(AZ\). Further report from S. Lucas relayed at 13:41 EDT: I just received word from J. Beish, that Carlos Hernandez \(A.L.P.O. Jupiter Recorder\), also witnessed the feature, and Don Parker was able to get a CCD image of same.... Nachdem sich B - obwohl noch auf Hubbles Mai-Aufnahme deutlich imposanter als A - fast ueberhaupt nicht bemerkbar machte, war C wieder 'normal' (Berichte ueber mehfache Ereignisse bestaetigten sich nicht), und D und E ebenfalls. Dann gab es eine laengere Pause, und der Impakt F war fuer das CTIO ideal plaziert, auch das weiter sehr unbestaendige Wetter schickte einige Wolken- luecken. Bloss der Impakt selbst fiel scheint's wieder aus! Inzwischen sind immer haeufiger mehrere 'Plumes' gleichzeitig zu sehen (so gelangen auf Hawaii [Keck!] und in Australien [ATT] spektakulaere IR-Bilder des engen Paars A und C), denn sie scheinen kaum Betrebungen zu haben, sich aufzuloesen. So war gestern abend auf dem Echtzeitmonitor des 4-m-Teleskops mit der OSIRIS-Kamera noch klar die Wolke D zu sehen (nicht sehr hell), und dann tauchte am anderen Rand ein sehr helles Gebilde auf, das aus zwei Wolken zu bestehen schien. War das jetzt die Rueckkehr von E, der neue Impakt F (wie von den 5 vorher gibt es keine verlaesslichen indirekten oder direkten Beobachtungen des Impakts selbst), oder war F gar dicht neben E gelandet? Zusaetzlich tauchte kurz vor der erneuten Verdichtung der Wolken auch noch die ueber 30 Stunden alte Wolke A am Rande auf - die Impakt-Plumes beginnen, den Anblick Jupiters im nahen IR und suedlich des STB bereits zu dominieren! Wie lange sie sich wohl halten werden? Und was sie wohl fuer Jupiters Wetter bedeuten? Hier eine kleine Auswahl von Meldungen zu den Impakten D bis F (UMD-Exploder): From: ma CCD imaging at Perth observatory of Io, Europa, and the limb of Jupiter=20 with a duty cycle of only about 30% did not reveal any obvious flashes=20 associated with the impact of fragment D. Photometric analysis will be required to remove large scintillation effects. Mike A'Hearn From VSM Sun Jul 17 15:24:11 1994 The impact of S-L 9 fragment D was first detected just before 11:55 UT with the CASPIR infrared camera on the ANU 2.3 m telescope, and the InfraRed Imaging Spectrometer, IRIS, on the 3.9 m Anglo-Australian Telescope at Siding Spring Observatory, Coonabarabran, Australia. This impact occured just as the impact site of fragment C reached the evening limb of Jupiter. Both CASPIR 2.34-micron images and IRIS K-grism cubes revealed a faint flash which faded within seconds. A second brighter flash was seen at 12:00 UT. This flash was about 4 times brighter than the fragment C impact site, and about half as bright as Europa in K-band, but it also faded in less than 1 minute at K-band. IRIS K-grism results then revealed a slow brightening from 12:18 UT until about 12:30 UT and a subsequent decay. From: Watanabe Jun-ichi 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. From lagage Sun Jul 17 17:55:42 1994 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 From herbst Jul 17 17:59:07 1994 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. 0098193B.1DC90D60.11862@mv.saao.ac.za Soon after the predicted time of impact of fragment E, a bright plume at the limb of Jupiter was seen at SAAO in the K band images. The development was similar to that of fragment A. As the impact site rotated into view a large bright spot, about half the diameter of the Great Red Spot was seen on the surface. Soon thereafter a second spot appeared at the limb and when it rotated further it was seen to be centred in a dark circular patch. By about 1800UT a third spot appeared at the limb, again apparently surrounded by a dark patch. Meanwhile, a dark circular feature centred near spots 1 and 2 could be seen easily in the eyepiece of the 0.75m telescope at SAAO, Sutherland. Stay tuned. John Menzies From: v8@ctio60.ctio.noao.edu (Visitor #8) We unambiguously confirmed CH4 nu3 line emissions, which appeared in our IRS/CTIO(1.5-m) spectra taken on the first impact area (A) around UT 0:30 (July 17). We made a model containing Jupiter and Earth atmospheres and including Doppler shift between Jupiter and Earth. We used auroral temperature-pressure structure and enhanced CH4 mixing ratio above 1 mbar (for the first bet), in order to fit the observed spectra. The agreement between the model and the observed emission structure is almost perfect. The covered spectral range is between 3.47 and 3.6 microns. We did not see any notable increase in H3+ emission around 3.53 microns, where a H3+ complex occurs. Sang Kim, Christophe Dumas, Jay Elias, Richard Elston. (Kim sowie Spencer mit seinen IR-Aufnahmen hielten gestern nachmittag bereits einen ersten Impakt-Workshop ab, wo u.a. dieses Ergebnis - wahre Instant Science - praesentiert wurde und Spencer die Nicht-Korrelation zwischen Kometengroesse und Effekt feststellte. Erklaeren kann das noch niemand. Spencer ist auch der Ansicht, dass die IR-Strahlung der 'Plumes' thermische Emission sein muesse, so hell wie die sei, und nicht nur ein Kontrastphaenomen von Kondensaten gegenueber dem dunklen Hintergrund.) From herbst Sun Jul 17 21:36:17 1994 We have continued to monitor the location of impact spots on Jupiter from the 3.5m telescope on Calar Alto. At UT 18:26, three spots are visible, a bright one just past the central meridian, a fainter one approaching the central meridian, and the faintest one just coming over the East limb. The positions of the spots correspond to the predicted locations of fireballs E, A, and C, respectively. At 2.3 um, the brightest spot is 15-20 times fainter than Io, and the fainter spots are down by further factors of about 1.5 and 2.2. From: Number Cruncher Hello world. It's cloudy today at Las Campanas, but last night it was clear enough to obtain an interesting result. Io appears to have changed color during the time that fragment B impacted Jupiter. The spectrum became increasingly red starting around 2:50 UT (July 17 1994) compared to its color 20 minutes later and 3 minutes earlier (when we started the observations...just in time !). The reddening continued to increase until 2:53 UT. Then the color started to drop back to the color we consistently observed from 2:57 until 3:07 UT. One other brief episode of reddening at 2:58 UT may have occured, but the flat field of our spectrum is screwy there (not in the earlier minutes). These observations were obtained with a corongraph/spectrograph built by Steve Larson of the University of Arizona and used by David Rabinowitz and Harold Butner (Carnegie Inst. Washington, Dept. Terrestrial Magnetism) at the Dupont 2.5m at Las Campanas. The integration times were 1 s, with exposures every 3 to 4 seconds, and the measured wavelength range was 0.3 to 1.0 microns (the sensitivity range of the Las Campanas Tek1 CCD). If Io's color change is the effect of reflected light from the impact, then the observations imply a duration of 7 minutes for the impact flash from fragment B. This would be an indication that fragment B was a diffuse cloud of large meteors by the time it hit Jupiter. D. Rabinowitz H. Butner Las Campanas 1994 July 17 Dies ist aber auch der einzige Bericht eines Mond-Effekts geblieben, insbeson- dere im Zusammenhang mit dem merkwuerdigen Impakt B. From: John Rogers This evening from 19.52 UT, I observed Jupiter visually with a 30-cm refractor at University of Cambridge, before sunset using yellow and polaroid filters. At the predicted impact sites A and C there are conspicuous dark spots, similar to oval BC in size or slightly larger; they have clearly grown since the first Hubble image. Site A was the darker, similar to the NEB in darkness, and remained visible until at least 20.25 UT when it was close to the limb. Site C was on the central meridian at 19.52 UT (+/- 3 min), giving System II longitude 148; oval BC was recorded at longitude 153. =20 John Rogers British Astronomical Association. Na, wer sagt's denn! Aehnliche Berichte wurden bereits eingangs erwaehnt. From PWC Mon Jul 18 01:46:19 1994 Observers should note that our predicted impact times refer to the actual impact at the 1 bar level of Jupiter's atmosphere and not the times that plumes should be observed. Depending upon the model used, the plumes will be observed something on the order of 5 minutes after impact. Even so, the predicted impact times for A, and C, and to a lesser extent D and E, appear to be early by an amount that is roughly equal to our 2-sigma uncertainty estimates. For some of the fragments, we note that our most recent astrometric data has tended to move the predicted impact times later. If this trend were to continue, we would expect our July 16th prediction for the impact time for F to be early by about 10 minutes. We encourage observers to use at least +/- 3-sigma windows about the predicted impact times. P. Chodas and D. Yeomans July 17, 1994, 23:25 UT From rwest Mon Jul 18 03:22:48 1994 Despite resonably good sky conditions until 01:00 UT, no effects were seen at La Silla which could be associated with impact F, predicted time 00:29 UT (3.6-metre + TIMMI: 10 micron imaging; 2.2-metre + IRAC2B: 2.2 micron imaging; DK 1.54-metre + special CCD camera; 1-metre + multi-channel high-speed photometer). The sky deteriorated after this time. From spencer Mon Jul 18 03:25:03 1994 We did not see a "fireball" from impact F between 00:12 and 01:10, though we had some gaps due to clouds of a couple of minutes. However a spot appaered on the terminator at around 01:10, similar to the old D site in brightness. We are about to take a spectrum of it... Spencer, DePoy, OSIRIS, CTIO 4-meter. From rwest Mon Jul 18 03:33:40 1994 The observers at the 3.6-metre and 2.2 metre telescopes (Tim Livengood, Ulli Kaeufl, Klaus Jockers) report sighting the F-plume at the limb at about 01:20 UT. More to follow. Derweil ein eiskalter(!) Bericht vom Suedpol - SL9-Beobachter sind ueberall... From lloyd Mon Jul 18 03:50:00 1994 SPIREX detected a fragment E impact site shortly after expected impact at 15:18 UT, at a comparable brightness to fragment A, at a wavelength of 2.36 microns. This data has only just become available as the South Pole communications satellites are only intermittently visible from the South Pole. The SPIREX fragment D data was significantly compromised due to the sudden onset of low blowing snow. The telescope was heroically cleared of accumulated snow by Joe Spang of the AMANDA project, and John Briggs of the ATP project, in strong winds at temperatures of -60 degrees Celsius. 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 From wdc Mon Jul 18 04:13:22 1994 Observations with the McDonald 2.7m telescope using ROKCAM at 2.3 microns did not show an obvious flash for the impact of object F within 30 minutes of the predicted time. The impact site of piece D was clearly visible. At 1:17UT a bright spot was seen on the east limb. Although it is possible that this bright spot is the impact of F with a substantial time delay past the predictions, it is somewhat more likely that this is the impact spot of piece E. The surface brightness of this spot is greater than the south polar hood. The observations were confirmed with CCD imagery with the 0.8m telescope at 893nm. The CCD images also show the impact site of piece D. The McDonald Comet Impact Science Team From spencer Mon Jul 18 04:23:04 1994 The impact F site is now as big as the Great Red Spot and shows two components, one many degrees of latitude south of the other, at 2.3 microns. Considerably brighter than=20 the south polar cap now (at 02:10 UT). South component is fainter. How do the impact sites get so big so fast? From spencer Mon Jul 18 04:33:51 1994 The MacDonald team may be right that the very bright and complex spot we are now observing is the old E site, not the new F site. Perhaps the complex morphology is due to the overlap of the two impact sites, though? We now are observing the A impact site coming into view at the start of its 4th rotation. Spencer, DePoy, OSIRIS, CTIO 4-meter From tozzi Mon Jul 18 04:43:13 1994 We observed Jupiter from 20:20 UT to 21:10 on the 17 of July with the IR Arcetri NIR NICMOS3 camera (ARNICA) through methane (2.35 micron) and continuum filters (1.58 micron) at the italian TIRGO telescope. Two bright spots are clearly visible in the methane images; the spots are located close to the southern polar cap (at about the longitude of the SL9 impact zones), on the west side. The brighter one is at the west limb while the weaker one is at about 40-60 degrees from the limb. During the observations the intensity of the brighter spot decreases as it crosses the limb of the planet. The other spot moves across the disk of Jupiter because of the rotation of the planet. From rwest Mon Jul 18 04:48:46 1994 Since the mentioned spot is also visible at 10 micron (3.6-metre, TIMMI) and the earlier spots have been very short-lived at this wavelength, it must be presumed that it is really the F plume which is now visible (see remark in Report from McDonald observatory). The E-site is probably very nearby. The F-spot is however unusual in that observations at 10 micron are still possible after more than 1 hour after the first sighting (Benoit Mosser). Laurent Jorda and Nick Thomas (DK 1.54 metre), at 02:00 UT find that the F-spot is well visible at 8937 A (CH4), but not at 7271 A (CH4), nor 8920 A (continuum). The spot is elongated in latitude (about 2.5 arcsec). The visibility at 8937 A is confirmed by U. Carsenty at the 60 cm Bochum telescope. From: mike brown Lick Observatory 40-inch reports: Using an 8950A/90A wide filter, we are observing two bright spots on the approaching limb, consistent with the locations of the A & E impact sites. The first site (presumably E) became visible at 18 July 02:37 UT, and currently has a brightness of 65% compared to the south polar hood. The second site (A) is still close to the limb, with a brightness of 35% of the south polar hood. From lasilla0 Mon Jul 18 07:57:33 1994 European Southern Observatory 3.6 m - TIMMI At about 1:27 UT (~45 min post impact), the plume of impact F was observed at the south-east limb of Jupiter. The plume remained at the limb for > 20 minutes, indicating that the plume was observed prior to the time it actually crossed the limb. We infer that the plume extended to a substantial altitude above the cloud tops; determination of the precise altitude will depend on detailed analysis of the impact-spot's longitude. The F impact residual was detected in infrared filters from 5 microns to 12 microns. From colas Mon Jul 18 08:08:33 1994 - Observations at Pic du Midi Observatory, 1-meter telescope (F/16) - 17 july 1994 from 18:30 to 23:15 UT - Infrared Camera : we have detected the spots resulting from each impacts E, C, A, B. We have missed at the present data reduction's state the expected feature from impact D. Spot A from yesterday has a reduced brightness under the methane band filter at 2.2 microns (band K). Spot E was observed 4 hours after impact and was strongly bright, but less than south polar cap and the GRS. However in the H band all spots lose their constrast and are now more difficult to watch. - CCD Camera : all the above features are very easily detected as a dark (low albedo) spot in the continuum from the blue to the red. In particular the newer spot E was very compact and dark. Spot C and A are more diffused specialy the last one. However under 890 nm (CH4 band) all spots are bright. Their sizes ranges from 5000 (spot E) to 10.000 km (spot A). Moreover our multi-wavelength observations in the continuum suggest that there is no a dominant color for all spots. We interpret that these spots are plumes of low albedo gray material upwarding from the comet's impact point and reaching a very high altitude. Was sagt man dazu? Nicht nur sind die Ereignisse wesentlich bedeutender als es selbst Optimisten erwartet hatten - und dann kommen auch noch mit die besten Beobachtungen aus, yuck, Europa und Nordamerika anstatt von der Sued- halbkugel. Hier haben jedenfalls die beiden Gruppen mit CCD-Kameras noch nichts wirklich berauschendes produziert, nur das OSIRIS-Instrument am 4- Meter-Teleskop und ein IR-Spektrograph am 1.5-Meter haben relevante Daten. Nun kommt ersteinmal wieder eine Durststrecke fuer den Cerro Tololo, und der naechste Absturz, das moeglicherweise groesste Fragment G, findet leider mit dem Jupiter unter dem Horizont am Morgen statt (ausserdem ist es eh' wieder bewoelkt - die 2 klaren Wochen Anfang Juli scheinen tatsaechlich eine Anomalie gewesen zu sein). Heute vormittag gibt es im Speisesaal eine grosse Pressekonferenz, und an- schliessend wird der Kontrollraum des 4-Meter-Teleskops gestuermt, wo John Spencer dann die schoensten Plumes auf den Monitor holen wird (das Bild vom vergangenen Abend, mit 3 oder 4 gleichzeitig und dabei ausgesprochen scharf, wird hoffentlich Eindruck machen). Mich hat derweil M. Hamuy offiziell beauftragt, im Foyer des 4-m-Teleskops die besten Bilder anderer Sternwarten auszustellen, nachdem meine Streifzuege im Internet weithin bekannt geworden sind (oefters kommen nachts Beobachter vorbei, um die neuesten Funde zu bestaunen). Ein weiteres Hubble-Bild wurde gestern publik, das gleichzeitig wie das erstveroeffentlichte entstand, aber in einer (mittelmaessig tiefen) Methanabsorption bei 900 nm. Das Gebilde, das im Violetten (und laut IAUC auch allen anderen Wellenlaengen) dunkel erschien, ist nur hier hell, sieht aber von der Form her praktisch gleich aus. Die spektakulaersten erdgebunde- nen Aufnahmen sind Bilder des Plume-Paares A+C, zum einen vom Keck, zum an- deren vom ATT in Australien. Zum Abschluss noch eine Hubble-Blitzanalyse aus einem IAU-Zirkular: PERIODIC COMET SHOEMAKER-LEVY 9 (1993e) The Hubble Space Telescope Team reports a location for the feature created by the impact of fragment A =3D 21. A streak ranges from jovicentric latitude B = -42 +/- 1 deg, System III longitude L = 186 deg to B = -39 +/- 1 deg, L = 188 deg. At 410 nm the maximum radial extent of the dark region surrounding the streak is 12 000 km. Although the region appears to be spatially circularly symmetric, the intensity distribution appears to be asymmetric, being more apparent to the south. A bright feature appears detached 1000-1500 km above the limb on July 16.846 UT in the 953-nm filter, but it is not present in an image 3-min earlier. A possible interpretation is that the feature is visible by reflected sunlight and that the apparent detachment is due to the shadow of Jupiter on the plume. 1994 July 17 (6024) Brian G. Marsden