Delta Aquarid Meteor Shower Fires Up For The Weekend

Meteors from southern Delta Aquarid meteor shower radiate from near the star Delta Aquarii (hence the name) not far from the bright star Fomalhaut in the Southern Fish low in the south before dawn. Created with Stellarium

It’s not a big shower, especially for the northern half of the planet, but if you’re up late this weekend and attentive, you’ll see more meteors than usual flashing across the sky. The annual Delta Aquarid meteor shower crests to a maximum tomorrow and Sunday mornings with 10-15 meteors per hour visible from a dark sky site.

Sky watchers in the southern hemisphere will see double that because the radiant, the point from which the meteors originate, is much higher in the sky. Meteors barreling down the sky south of the radiant don’t get cut off by the horizon.

When Earth’s orbit intersects rocky and icy debris left in the wake of comet tail, we experience a meteor shower. Illustration: Bob King

There are actually two meteor showers in Aquarius active this time of year – the northern and southern Delta Aquarids. The northern version sports fewer meteors and peaks in mid-August.

Both are very broad streams. Tomorrow’s southern “Deltas” started in mid-July and will peter out a month later. This weekend marks the peak.

Nearly all meteor showers originate from clouds of sand to seed-sized bits of debris fizzed off by comets as they swing near the sun. As a candy lover, I  like the image of Tootsie-Rolls tossed out at a parade.

Earth plows into these debris streams at specific times each year, creating a shower of meteors from the sky. Those bits of comet dust strike the air overhead at many thousands of miles an hour, burning up in a flash we call a meteor. Energy imparted to the air molecules by the speeding particles is converted into the light we see streaking across the sky.

A meteor from the April Lyrid shower burns up in the atmosphere some 70 miles high as seen from the International Space Station. Credit: NASA

The best time to watch the Delta Aquarids is in the early morning hours before dawn when the radiant is up in the southeastern sky. Happily, the gibbous moon will set around 1 a.m., leaving dark skies during the ideal viewing time. Find a spot with a good view to the south and set up a lawn chair. You don’t need any other equipment than your eyes … and maybe a cup or two of coffee. The Aquarids will whet your appetite for the bigger, better Perseid meteor show coming to Earth on Saturday night August 11-12.

Since most showers have a “parent” comet, you might be interested to know that the likely one for the Delta Aquarids is none other than 96P/Machholz. Yes, the very same comet that’s currently visible in medium-sized scopes low in the western sky during evening twilight. How nice to meet the artist and admire his work at the same time.

7 Responses

  1. Stephan

    Hi Bob,
    there’s one thing that always puzzled me about meteor showers, let me explain:
    The Earth is orbiting around the Sun, and I guess anything lingering on the Earth’s orbit around the Sun should be orbiting her, too. But meteor clouds, being comet debris, seem to stay in one place, as we come through those “clouds” every year at the same time, and meteors’ radiants point towards the same point. Shouldn’t anything that stands still in the solar system either drop towards the Sun or move outwards ?
    Greetings from Stuttgart

    1. astrobob

      Picture a comet orbit outlined by meteoric debris. Each year the Earth’s orbit intersects the comet’s orbit and for a day or two we pass through it to the other side. As we do, meteors appear to radiate from a point ahead (in our direction of motion through the cloud) just the way snow appears to radiate from a point in the distance when you drive through a snowstorm at night. The particles in the comet’s orbit are orbiting the sun. As a separate issue, some of those particles are probably the right size to fall inward toward the sun due to the Poynting-Robertson Effect. Does this help to explain your question?

      1. Stephan

        thanks for the helpful hint! Yes it helped – I understand that a comet does not necessarily circle the Sun in the plane of our (Earth’s and planets’) orbit. And so there’s only one intersection point between our circle and the track of the comet, outlined by the dust it leaves behind.
        Yep, now that’s cleared up. Thanks again, and a sunny greeting
        from Stephan

  2. Jeff Smith

    Hey Bob,

    I live in West Los Angeles and saw a large fireball at 8:30 pm (still quite light), streak directly overhead North and disappear over the mountains. I don’t see it reported anywhere. Is there a local (So Cal) site you can recommend where I can look to see details or are these so common, it’s a non-event. Again, this was no shooting star and quite large.

    Thanks –

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