The Draconids meteor shower takes place every year between the 6th and 10th of October with this year's peak occurring on the night of the 8th October. Normally the maximum ZHR (Zenithal Hourly Rates) for the Draconids is feeble with only 1 to 2 meteors, but the shower does have a history of spectacular outbursts and this year it is worth looking outside as there could well be another.
The dust and debris left behind from periodic comet 21P/Giacobini-Zinner as it orbits the Sun are the source powering the Draconids meteor shower and in reference to the parent comet the meteor shower has also been unofficially known as the Giacobinids.
With an orbital period of 6.6 years, Comet Giacobini-Zinner was discovered on the 20th December 1900 in Nice by French astronomer Michel Giacobini. The comet was subsequently lost and then re-discovered two orbits later on the 23rd October 1913 by German astronomer Ernst Zinner at the Remeis Observatory in Bamberg, Bavaria.
During apparitions, Giacobini–Zinner can reach 8th magnitude in brightness although it is known to flair, for example in 1946, when the comet brightened significantly to attain 5th magnitude and naked-eye brightness.
If the Earth happens to pass close to the orbit of the comet a short time before or after the comet has passed the same point then there is a chance of a major storm. In reality this means that a major storm is possible once every 13 years.
Historically, great storms have occurred in 1933 and 1946. In 1933 observers recorded an hourly rate of 6,000 meteors over a short period. Most meteors were slow moving and faint (between 3rd and 5th magnitude). Likewise a similar storm occurred in 1946 when many thousands of meteors were seen. On both occasions the Giacobinid activity was short, lasting only about 3 hours in total. Lesser but noteworthy outbursts occurred in 1952, 1985, and 1998, with lower rates but still of the order of hundreds of meteors an hour.
2011 Meteor storm
The last major burst in activity occurred in 1998 and there is a fair chance this year's event will be the next one.
However, here is a note of caution; there is a lot of uncertainty involved and the storm may be spectacular or a complete wash-out. What is usual for the Draconids is that any resulting meteor storm will be short lived. The most likely time is during peak of activity, sometime between 16h and 22h UT (Universal Time) on the 8th October. This is an ideal time for observers in Northern and Eastern Europe and if luck prevails there could be hundreds or even thousands of meteors an hour visible.
Where to look
The radiant is located in the faint far northern constellation of Draco the Dragon, not far from the bright star Vega. To locate the correct region of sky, look to the north-western part of the sky and a few degrees north-west of Vega to the head of the Dragon. The radiant is located near the star ν Draconis.
Unfortunately, there will be light interference from a waxing gibbous Moon in Aquarius, less than four days from full.
Comet 21P/Giacobini-Zinner Data Table
|Discoverers||Michel Giacobini and Ernst Zinner|
|Discovery date||20th December 1900|
|Aphelion distance (AU)||6.014|
|Perihelion distance (AU)||1.038|
|Semi-major axis (AU)||3.526|
|Orbital period (years)||6.621|
|Last perihelion||2nd July 2005|
|Next perihelion||11th February 2012|
Draconids Data Table
|Meteor shower name||Draconids|
|Dates||6th October -> 10th October|
|Peak Date||8th October|
|RA (J2000)||17hr 32m|
|ZHR||Variable: 1 to 2 (normal) 6000 (storm)|