Meteor experts are advising that parts of the world might enjoy enhanced activity from the Draconid meteor shower tonight – the 6/7 October.
This shower is produced by dust left by Comet 21P/Giacobini-Zinner which came close to Earth in 2018 and made an attractive display against a dark sky for binocular users and astrophotographers. The comet takes just 6.54 years to complete an orbit of the Sun.
In 2018, meteor observers saw the numbers of meteors (the ZHR) increase to 150 an hour for a time, though the meteors were largely faint. See our report of 2018’s Draconid meteor outburst.
The International Meteor Organization is advising that there could again be outbursts by the Draconids in 2020. They report that French meteor expert Jérémie Vaubaillon, of the Institute for Celestial Mechanics and Computation of Ephemerides, Paris, has predicted that activity from the Draconids will be enhanced on the night of 6/7 October when the Earth encounters two streams of dust ejected by the comet in 1704 and 1711.
According to IMO, NASA astronomer Peter Jenniskens predicts peak times for these encounters to occur on 7 October at 01:25 UT for the 1704 stream and 01:57 UT for that from 1711. It will be worth observing for as long as you can around these times.
These times are ideal for a large part of the northern hemisphere, from western Asia to North America. They occur in the early hours for Europe, for example, but in the evening for America’s east coast (where it will still be the 6th), when the radiant in Draco will be high in the sky.
The meteors are called Draconids because the shower’s radiant is in the constellation of Draco, the Dragon, not far from the bright star Vega. They are sometimes also known as the Giacobinids after the name of the comet.
Usually, the Draconid meteor shower is an insignificant event, providing only a very few meteors at maximum. However, in the past meteor rates have soared when the comet is near Perihelion, its closest point to the Sun in its highly elliptical orbit.
This shows that, rather than becoming evenly distributed along its orbit, the meteor particles are still bunched up close to the comet itself. So when the Earth passes through the stream every year, it encounters differing quantities of this meteor dust.
The Draconids in history
In 1933 and 1946, rates of Draconid meteors were so high that thousands of meteors an hour could be seen for a time. Such outbursts are known as meteor storms.
The 1933 storm was witnessed by the Rev. W.F.A. Ellison, former Director of Armagh Observatory in Northern Ireland. He wrote a colourful report in the Belfast Telegraph, which you can read in full here. He wrote: “. . . it was apparent that a really great meteoric storm was in progress. I counted 200 meteors in two minutes, and then counting became impossible. The fire-stars became as thick as the flakes of a snowstorm. Instead of twos and threes they came in flocks and gusts. The sky was thick with them wherever one looked.”
Draconid meteor shower rates peaked again, to a lesser extent, in 1998 and again in 2005, 2011 and 2012. The meteors are slow-moving compared to meteors from other showers.
Comet 21P reached perihelion on September 10, 2010, just a month before this year’s crossing of the meteor stream by the Earth. The shower is recorded as being active from October 7th to 10th, with its usual peak on the night of October 8th/9th.
So what can we expect from the Draconid meteor shower in 2020? The honest answer is that no one can say, but conditions are such that we could enjoy some enhancement of rates. It will be worth keeping an eye on the sky to see what happens, despite the presence of a bright gibbous Moon!
The Draconid meteor shower’s radiant is in the far northern constellation of Draco, the Dragon, so this shower is not one for those of you in more southerly cities such as in Australia, New Zealand and South Africa.
Related: What’s in this month’s night sky