[meteorite-list] Bavaria Bolide: the same orbit that Pribram meteorite!!
From: vincent jacques <meteorh3_6_at_meteoritecentral.com>
Date: Thu Apr 22 09:50:27 2004 Message-ID: <F174Ti68KtBsejEBCuD00001e2d_at_hotmail.com> <html><div style='background-color:'><DIV>Hello all, ther is a CC from Pavel Spurny about the german bolide. Very very interesting!!!!!! </DIV> <DIV> </DIV> <DIV> </DIV> <DIV> </DIV> <DIV>Dear all,<BR><BR>I am sending you the information about the results on the EN060402 bolide<BR>which was observed by many people over a large teritorry of Central Europe.<BR>As you can read below, it was a really exceptional case.<BR><BR><BR>The April 6, 2002 fireball<BR><BR> A very bright fireball illuminated large territory of Western Austria<BR>and Southern Bavaria on Saturday evening, April 6 at 22:20:18 local time<BR>(UT+2h). The fireball was observed by many casual witnesses over the territory<BR>of almost whole Central Europe, but most observations were reported from Bavaria<BR>and Western Austria. Except of numerous visual observations, the fireball was<BR>recorded by several kinds of scientific instruments. The most important records<BR>were obtained by the systematic long-term observational photographic program -<BR>the European Fireball Network (EN). The records were taken at 5 German, one<BR>Czech and one Austrian station of the EN. Each of these stat ions is equipped<BR>with one all-sky camera, which is open whole night and whole sky is photographed<BR>on one image. The German and Austrian stations are equipped with mirror all-sky<BR>cameras and are operated by the German Aerospace Center DLR, Berlin. The Czech<BR>stations of the EN are equipped with very precise Zeiss Distagon fish-eye<BR>objectives and are operated by the Astronomical Institute of the Academy of<BR>Sciences of the Czech Republic, Ondrejov. Most Czech stations had cloudy skies<BR>on April 6, however. The photographic records are most important for exact<BR>determination of the fireball atmospheric trajectory, including prediction of<BR>meteorite impact area and derivation of heliocentric orbit. In addition to these<BR>photographic data, the fireball was recorded by three radiometric systems placed<BR>in the Czech Republic at Ondrejov Observatory and Kunzak station, which gives us<BR>basic information about light curve and maximum brightness of the<BR>fireball and about exact time of the event. Furthermore the fireball was<BR>recorded by at least at two infrasound stations, one located at Freyung, Germany<BR>(see <A target=_blank href="http://64.4.8.250/cgi-bin/linkrd?_lang=FR&lah=de312f6276c163fc53279a26d4ae456e&lat=1019084991&hm___action=http%3a%2f%2fwww%2eseismologie%2ebgr%2ede"><FONT color=#000099>http://www.seismologie.bgr.de</FONT></A>) and second at Deelen, The Netherlands (see<BR><A target=_blank href="http://64.4.8.250/cgi-bin/linkrd?_lang=FR&lah=c707034ce6bf52b48dfc5dc7d1e1997a&lat=1019084991&hm___action=http%3a%2f%2fwww%2eknmi%2enl%2f%7eevers%2finfrasound%2fevents%2f020406%2fbavaria%2dbolide%2ehtml"><FONT color=#000099>http://www.knmi.nl/~evers/infrasound/events/020406/bavaria-bolide.html</FONT></A>) and also<BR>at several seismic stations from Austria, Southern Germany and Switzerland.<BR><BR> All data presented below are based only on above-mentioned photographic<BR>and radiometric data recorded within the EN obs erving program and are very close<BR>to final values. All records were measured, reduced and all computations were<BR>performed at the Ondrejov Observatory, the headquarters of the European Fireball<BR>Network.<BR><BR> The fireball started its almost 92 km long luminous trajectory at an<BR>altitude of 85.6 km about 15 km NE from Innsbruck, Austria (longitude 11.564 deg<BR>E, latitude 47.304 deg N). Maximum brightness of about -18 absolute magnitude<BR>was reached in a bright flare at a height of 21 km near Garmisch-Partenkirchen,<BR>Germany (longitude 10.91 deg E, latitude 47.51 deg N). The fireball terminated<BR>at an altitude of only 15.8 km about 20 km W from Ga-Pa (longitude 10.85 deg E,<BR>latitude 47.53 deg N). Such deep penetration of a fireball is very scarce and<BR>this fireball belongs to the deepest ever-photographed fireballs in the history.<BR>It also implicates, that some part of the initial mass survived the ablation<BR>processes in the atmosphere and landed on the ground as meteorites. The slope of<BR>the atmospheric trajectory to the Earth's surface was 49.5 degrees. The fireball<BR>entered the atmosphere with the velocity of 20.9 km/s and during its flight<BR>substantially decelerated to the final value of only 4 km/s, when ablation<BR>process was stopped. According to the dynamic behavior in the atmosphere this<BR>fireball belongs to the fireball type I, which is usually identified with stony<BR>material, mostly ordinary chondrites. The initial dynamic mass of the entering<BR>meteoroid was about 500 kg and most of this mass was ablated and only about 30<BR>kg of total mass could land on the ground in several fragments. The impact area<BR>is relatively large, it is at least several kilometers long and about 1km wide.<BR>The main fragments will lie eastwards from Schwangau, Germany. Smaller fragments<BR>could be found also around the Austria-Germany border westwards from Ga-Pa. The<BR>whole area is located in high mountains (the Alps), which is unfortun ately very<BR>unfavorable for any systematic search.<BR><BR>From the exact time of the fireball occurrence, its initial velocity, and the<BR>position of the radiant, we computed the heliocentric orbit. We found that the<BR>body, before its collision with Earth, orbited the Sun on an elliptic orbit<BR>defined by the following orbital elements: semimajor axis 2.4 AU, eccentricity<BR>0.67, perihelion distance 0.79 AU, argument of perihelion 241.4 degrees,<BR>longitude of ascending node 16.8 degrees and inclination 11.4 degrees. Such kind<BR>of heliocentric orbit is quite usual for fireballs which penetrate very deep<BR>into the Earth's atmosphere and which can produce meteorites. The aphelion of<BR>these orbits lies in the main belt of Asteroids and therefore the asteroidal<BR>origin of these bodies is inferred. However, the heliocentric orbit of this<BR>fireball has one very significant exceptionality: we found that this orbit is<BR>the same as the orbit of the first photographed meteorite fall in the history -<BR>the Pribram meteorite fall on April 7, 1959. Both orbits are so close that there<BR>is no doubt that both bodies have the same origin. It is very important evidence<BR>for the existence of asteroidal streams and meteorite streams as suggested<BR>earlier by Halliday and others. From observations of both bolides we know that<BR>both bodies were far from each other in the orbit (probably about half of the<BR>period) when the Pribram collided with the Earth. It implies that many such<BR>bodies have to be on this orbit, because it is fantastic chance to photograph<BR>two meteorite falls from the same orbit on practically the same territory within<BR>only 43 years! It also substantiates why it is important to operate such long<BR>term observing program as the European Fireball Network is.<BR><BR>Finally, from the perfect similarity of both heliocentric orbits we can<BR>predicate, that both bodies had also the same composition and therefore we can<BR>expect that meteorites produced by the April 6 fireball are H5 ordinary<BR>chondrites.<BR><BR>Pavel Spurny<BR>Astronomical Institute of the Academy of Sciences<BR>Ondrejov Observatory<BR>The Czech Republic<BR>e-mail: <A target=_top href="http://lw9fd.law9.hotmail.msn.com/cgi-bin/compose?curmbox=F000000005&a=77b6297db9386d1b381622909a73edd3&mailto=1&to=spurny_at_asu.cas.cz&msg=MSG1019083546.27&start=1833661&len=8747&src=&type=x"><FONT color=#000099>spurny@asu.cas.cz</FONT></A><BR></DIV></div><br clear=all><hr>Discutez en ligne avec vos amis, essayez MSN Messenger : <a href='http://g.msn.com/1HM208001/e'>Cliquez ici.</a><br></html> Received on Wed 17 Apr 2002 07:14:07 PM PDT |
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