Magical Dinosaur

If you see a shooting star around now, it likely is one of the meteors called Draconids.

It certainly is – wherever it appears in the sky – if you compare its path with the stars you know and can see that the path points away from the head of Draco, the vast Dragon that winds around the celestial north pole.

Draconids may be seen between about October 6 and 10; their peak this year is predicted for Friday October 9 around 6 hours Universal Time. This (by clocks still on summer Daylight-Shifting Time) is 7 AM for Britain, 2 AM for eastern North America, and 11 PM back in Thursday October 8 for the Pacific zone.

The peak times given for meteor showers are to be taken with pinches of less or more salt. The prediction may be off by a few hours, the peak may be sharp or it may be soft – not really a great difference from hour to hour. The “Dragon’s Children” are appropriately cussed. Some years, they don’t show up at all. But some years, they come out like blazes from a furious dragon’s maw.

This happened for example in 1946, when watchers in the southwestern US reported that they saw up to 10,000 an hour, despite the glare of a Full Moon! That’s about three a second, and this year the Moon isn’t a problem (it rises about 3 AM).  So be prepared to count hard. – Just kidding: if such a thing happens, which it probably won’t, you’d have to do your best to estimate the number you see in, say, a minute, and then multiply by 60. This would be an estimated “hourly” rate, though it might keep up only for a fraction of an hour.

It would certainly be worth reporting, to me, I guess. Such results can be used by experts (to whom I would pass them) fpr calculating what they call the Zenithal Hourly Rate, which can be used for calculating further information about the nature and origin of the meteor stream. But they’d need to know exactly what the time was, where you are (your city) and what your sky conditions were like, as well as you can describe them.

Constellation Draco winds around the celestial north pole, and the part of it from which these meteors appear to radiate is near to (only 13 degrees from) the ecliptic north pole. What this means is that the meteors are coming down almost vertically from the north into the plane of our orbit around the Sun. This in turn means that they plow into our atmosphere relatively slowly – “only” about 20 kilometers per second – by contrast with the meteors of some other showers that meet us nearly head-on and therefore up to three and a half times faster.

And what is the origin of the Draconids? They are roughly following the orbit of Comet 21P Giacobini-Zinner, which comes by each 6.6 years and last did so in 2012. Sp the meteors have also been known as the Giacobinids, as if they are the children of Michel Giacobini rather than of a magical dinosaur. Most Draconids we see are faint; they are (or were before burning up) specks or clumps of dust that separated from the comet centuries ago. This is the kind of information that is founded on people’s reports of meteor counts.