[BAA-ebulletin 01016] An interesting return of the October Draconid meteors

[BAA electronic bulletins service]

The October Draconid meteor shower produced two outstanding meteor 
storms in 1933 and 1946 and lesser showers in 1926, 1952, 1972 (very 
weak), 1985, 1998, 2005, 2011 and 2012 (mainly very faint meteors). All 
the observed showers occurred when the parent comet, 
21P/Giacobini-Zinner passed close to the orbit of the Earth.  In 2018, 
Earth will be passing just 0.0171 AU (256,000 km) inside the orbit of 
comet 21P/Giacobini-Zinner on October 9.0, only 22.7 days after the 
comet itself passed through the same region of space.  At first glance 
this would appear to be somewhere in between the circumstances in 1933 
when there was a meteor storm over Europe with a ZHR ~ 5000 m/h and 
those pertaining in 1985 when there was a significant shower over Japan 
with a ZHR ~850 m/h.

However, modelling of the individual narrow dust trails laid down by the 
parent comet at successive returns to perihelion shows that no major 
activity is likely this October, as the trails mostly pass too far from 
the Earth. Closest approach will be to the 1953 trail at a distance of 
0.00249 AU. Unfortunately, this trail is probably only sparsely 
populated due to the close encounter with the Earth in 1985. 
Consequently, there may be some low activity from this trail, with ZHR 
of 10-20 m/h, sometime between 23:00 UT and 00:30 UT on October 8/9 
(Monday-Tuesday).

However, unexpected brief outbursts in activity are always possible, so 
observations are encouraged throughout the night of October 8/9.  The 
radiant of the shower will be centred on RA 17h 32m, Dec + 56o, not far 
from the star Nu Draconis in the ‘head’ of Draco. Draconid meteors are 
typically very slow moving, in marked contrast to members of showers 
such as the Perseids or Leonids.

With new Moon occurring on October 9, there will be no interference from 
moonlight this year. Observations will also be of value on the evenings 
immediately before and after the predicted peak to provide a check on 
background meteor rates at this time. Let us hope for clear skies 
everywhere on the evenings of 2018 October 7, 8 and 9, but particularly 
on October 8/9.

The BAA Meteor Section is seeking the help of all observers to gain an 
accurate picture of Draconid meteor activity this year. We would welcome 
any observations of the Draconid meteor shower from individuals or local 
society groups.  Even simple counts of Draconid and sporadic meteors 
seen within given time periods will be welcome.  Please send your 
observations to meteor at britastro.org.

This e-bulletin issued by:

Dr John W Mason
Director, BAA Meteor Section

2018 October 4