The 2005 Draconid outburst

Abstract

Aims. We report the flux profile and mean orbit for meteoroids associated with an unexpected activity outburst from the Draconid meteor shower on 8 October, 2005. The primary aim is to define the characteristics of the outburst and establish the age of the associated meteoroids. Methods. Radar data from the outburst are used to define the flux profile and mass distribution for Draconid meteoroids at small meteoroid masses, while visual data are used to define the ZHR profile at larger masses. The radar recorded both single station and orbital data permitting orbits for many individual Draconid radar echoes as well as determination of a mean shower radiant. Results. The peak activity was centered at 16.1 hrs UT, (λ = 195.• 42 (J2000) solar longitude) with noticeably heightened radar activity lasting for a total of more than three hours. Based on the distribution of amplitudes for underdense Draconid echoes, the mean mass distribution index at masses of 10 −6 kg was found to be 2.0 ± 0.1. The equivalent hourly-binned radar ZHR was in excess of 150, while visual observations in the same intervals produced ZHRs of 40. The apparent radiant of the outburst was α = 256.9 ± 2.2• , δ = +56.6 ± 1.8• . Numerical modelling of radar-sized Draconids show that a significant number of meteoroids from the 1946 perihelion passage of 21P/Giacobini-Zinner encountered the Earth over the interval 195.• 23 ≤ λ ≤ 196.• 0 in 2005, centred about 195.• 50 Conclusions. The shower was rich in faint meteors, and therefore showed higher activity in radar data than in visual data alone. The duration of the outburst was very similar to past returns, while the mean radar stream orbit was somewhat different than previous measurements (the radiant differed by 6• in right ascension and 2• in declination) and also from the expected distribution of orbital elements for modelled 1946 meteoroids encountered in 2005.

Optical observations of enhanced activity of the 2005 Draconid meteor shower

“…The determination of the mass distribution index suffered from low number statistics, nevertheless, it seems that the index was similar to that in 1998 and somewhat lower than that in 1985. The radiants of several Draconids recorded simultaneously from two stations lie close to the theoretical value of Campbell-Brown et al (2006) and also to the radiants reported in other papers describing earlier Draconid outbursts. We did not observe meteors from the radiant detected by the radar, which was shifted by about 4 degrees to the West.…”

“…For the rest of the night the numbers of meteors did not exceed the annual Draconid level. This result is in good agreement with the observations of Campbell-Brown et al (2006). According to their paper the maximum activity occurred at 16.1 UT.…”

“…On the basis of the video observation of the Draconids meteor shower in 2005 we can confirm the enhanced activity reported by Campbell-Brown et al (2006). The number of optically detected meteors was not as high as the radar (i.e., fainter) meteors.…”

“…Thus the observers were encouraged to look for some signs of higher activity of this shower. Campbell-Brown et al (2006) reported the Draconid outburst, which occurred around the solar longitude λ = 195.42…”

Atmospheric deceleration and light curves of Draconid meteors and implications for the structure of cometary dust

“…We employed double-station observations with image intensified video cameras on three nights from October 6 to October 9, 2005. A higher than expected activity of the Draconid shower occurred in the evening hours on October 8 (Campbell-Brown et al 2006, and Paper I); we observed the end of this activity between the evening twilight and about 19 UT. Unfortunately, because of poor weather at the second station (Třebíč), most meteors observed during this period were detected only in Ondřejov.…”