Real-time Flux Density Measurements of the 2011 Draconid Meteor Outburst

During the 2011 outburst of the Draconid meteor shower, members of the Video Meteor Network of the International Meteor Organization (IMO) provided, for the first time, fully automated flux density measurements in the optical domain. The data set revealed a primary maximum at 20:09 UT $\pm$5 min on 8 October 2011 (195.036 deg solar longitude) with an equivalent meteoroid flux density of (118 $\pm$10) x 10^-3 km^-2 h^-1 at a meteor limiting magnitude of +6.5, which is thought to be caused by the 1900 dust trail of comet 21P/Giacobini-Zinner. We also find that the outburst had a full width at half maximum (FWHM) of 80 minutes, a mean radiant position of alpha=262.2 deg, delta=+56.2 deg ($\pm$1.3 deg) and geocentric velocity of v_geo=17.4 km/s ($\pm$0.5 km/s). Finally, our data set appears to be consistent with a small sub-maximum at 19:34 UT $\pm$7 min (195.036 deg solar longitude) which has earlier been reported by radio observations and may be attributed to the 1907 dust trail.