A strong outburst of the October Draconid meteor shower was predicted for 2011 October 8 .
Here we present the observations obtained by the Canadian Meteor Orbit Radar ( CMOR ) during the 2011 outburst .
CMOR recorded 61 multi-station Draconid echoes and 179 single-station overdense Draconid echoes ( covering the magnitude range of +3 \leq M _ { V } \leq + 7 ) between 16-20h UT on 2011 October 8 .
The mean radiant for the outburst was determined to be \alpha _ { g } = 261.9 ^ { \circ } \pm 0.3 ^ { \circ } , \delta _ { g } = +55.3 ^ { \circ } \pm 0.3 ^ { \circ } ( J2000 ) from observations of the underdense multi-station echoes .
This radiant location agrees with model predictions ( e.g . ) to \sim 1 ^ { \circ } .
The determined geocentric velocity was found to be \sim 10 - 15 \% lower than the model value ( 17.0 - 19.1 \mathrm { km \cdot s ^ { -1 } } versus 20.4 \mathrm { km \cdot s ^ { -1 } } ) , a discrepancy we attribute to undercorrection for atmospheric deceleration of low density Draconid meteoroids as well as to poor radar radiant geometry during the outburst peak .
The mass index at the time of the outburst was determined to be \sim 1.75 using the amplitude distribution of underdense echoes , in general agreement with the value of \sim 1.72 found using the diffusion-limited durations of overdense Draconid echoes .
The relative flux derived from overdense echo counts showed a similar variation to the meteor rate derived from visual observations .
We were unable to measure the peak flux due to the high elevation of the radiant ( and hence low elevation of specular Draconid echoes ) .
Using the observed speed and electron line density measured by CMOR for all underdense Draconid echoes as a function of height as a constraint , we have applied the ablation model developed by .
From these model comparisons , we find that Draconid meteoroids at radar sizes are consistent with a fixed grain number n _ { grain } = 100 and a variable grain mass m _ { grain } between 2 \times 10 ^ { -8 } ~ { } \mathrm { kg } and 5 \times 10 ^ { -7 } ~ { } \mathrm { kg } , with bulk and grain density of 300 ~ { } \mathrm { kg \cdot m ^ { -3 } } and 3 ~ { } 000 ~ { } \mathrm { kg \cdot m ^ { -3 } } , respectively .
One particular Draconid underdense echo displayed well-defined Fresnel amplitude oscillations at four stations .
The internal synchronization allowing us to measure absolute length as a function of time by combining the absolute timing offsets between stations .
This event showed clear deceleration and modelling suggests that the number of grains for this meteoroid was of the order of 1 000 with grain masses between 10 ^ { -10 } and 10 ^ { -9 } kg , and a total mass of 2 \times 10 ^ { -6 } kg .