Results from the Aurigid MAC Mission


Peter Jenniskens, Carl Sagan Center, SETI Institute
We predicted the encounter of Earth with the dust trail of comet C/1911 N1 (Kiess) on 2007 September 1, when an outburst of meteors was expected from a radiant in the constellation of Auriga (EOS, Aug 7 issue). We anticipated that the shower would be best seen from the western states of the USA, Canada, and Mexico, including Hawaii and Alaska. It would be the only such Aurigid shower outburst in our lifetime. The meteoroids dated back to ejection around 4 A.D., give or take 40 years. These Aurigids were our best chance yet to study the 1-revolution dust trail of a known long-period comet, for measurements of the dust ejection conditions, and for clues about the possible presence of a cosmic ray induced crust in a comet which only recently returned from the Oort cloud. An airborne observing campaign was organized, called the Aurigid Multi-Instrument Aircraft Campaign, involving two Gulfstream GV aircraft, which were deployed from NASA Ames Research Center in Moffett Field, California. This enabled a team of 24 researchers, with an array of different cameras, to observe the shower from an altitude of 47,000 ft. The shower manifested much as expected, with a peak rate of about ZHR = 100 /hr, a peak time of 11:15 +/- 5 min. UTC, a duration of about 2 hours, and an abundance of bright +3 to -2 magnitude meteors. The shower was also well observed from the ground by both professional and amateur astronomers. Here, we will present some of those first results, discuss the shower's impact on the public, summarize the predictions, compare those to the observed shower activity, and report on the ongoing investigation of comet Kiess and its meteoroid stream. More information: http://aurigid.seti.org