Astronomy Buff

The Aurigids Are Coming! This Rare Meteor Shower Has Happened Only Three Times

by Tony on August 14th, 2007

I admit I don’t take as many meteor showers as I should, they’re cold, sometimes damp, and they make me very sleepy, but there is one coming up that I’ll have to take: the Aurigid meteor shower.

If you live in the western U.S., Canada or Mexico then you can take a shower with me. On September 1, 2007 a very brief shower of unusual meteors will radiate from the constellation Auriga.

This particular meteor shower has only occurred a handful of times (1935, 1986 and 1993) and this year marks the last time we’ll ever see it. Models for this year’s event show that it may be quite impressive: we may see 200 meteors per hour in a short 10-minute time interval. This is about three times the peak rate of the annual Perseid meteor shower.

Here are some characteristics of the Aurigid meteor shower:

• Very rare. The Earth has only passed through this debris field three times: 1935, 1986, 1993
• The event itself is relatively short, lasting only about 1 to 1.5 hours long.
• It has relatively bright meteors, ranging from -2 to +3 magnitude.
• There are a high number of meteors, about 200 per hour in a short 10 minute time interval at the peak. That’s about three times the peak rate of the annual Perseid meteor shower.
• Very unusual colors, many meteors may appear greenish or bluish as they burn up in the atmosphere. This suggests high levels of ablating iron and magnesium atoms.

If you don’t take a meteor shower at all this year (and please folks, you should shower WAY more than that… I’m just sayin’), this is the one to take.

The image above shows what the Earth will look like from the perspective of the dust grains as the Earth approaches them. The terminator marks where the shower will be visible, if you’re in the dark parts, you can see it. As you can see, folks in Hawaii and Alaska are very well positioned to see this as well.

The peak of the meteor shower will occur at about 11:36 UT (5:36 MDT) but you should get up about an hour before that because the forecasting models have error bars of +/- 25 minutes. You’ll need to get up pretty early in the morning for this one, but you won’t have to stay out as long since it’s only going to last about an hour.

Why is this event so rare and why is this the last time we’ll see it?

Around 83 B.C., a very long period comet named Kiess ejected a cloud of dust particles inside Earth’s orbit as it passed by the Sun. Comet Kiess has a really long period, the last three times it came into the inner solar system occurred in 1911, 83 B.C. and about 2000 years prior to that. This thing doesn’t get out very much.

The dust particles were pushed by the solar wind for the last 2000 years or so into slightly wider orbits, forming a thin stream of dust that lies just outside the Earth’s orbit.

Every once in a while the combined gravity of the planets in the solar system moves the dust into the path of the Earth, resulting in a meteor shower as the Earth passes through it.

Models attempting to predict the path of the dust particles suggest that over the next 50 years, the dust trail will move in and out of the Earth’s path but they will not hit the Earth again. This is the last time we will encounter this dust trail.

Given the rarity of the event and the potential for spectacularity (ooh, is that a word?), I suggest you get yourself up that morning and check it out.

Image Credit: Me and Stellarium
(yes, I know the arrows look like a monkey did it)

Top Image Credit: Me flying around with Celestia

(Reference: “An Unusual Meteor Shower on 1 September, 2007″, P. Jenniskens and J. Vaubillion. EOS Vol. 88, No. 32, 7 August, 2007)

Technorati Tags: aurigid meteor shower, aurigids, comet kiess

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POSTED IN: observing the night sky