Eta Aquarid meteor shower from Halley’s Comet peaks this weekend

The Eta Aquarid meteor shower peaks tomorrow morning May 5. This map shows the sky facing east at dawn for mid-northern latitudes. The shower radiant (red) is near the star Eta in the constellation Aquarius to the right of the Great Square of Pegasus. The crescent moon and Comet Lemmon, visible in binoculars, will also join the scene tommorow. Stellarium

Up for another early morning meteor shower? Then get ready for the Eta Aquarids (AY-tuh ah-QWAR-ids) which peak tomorrow in the quiet hours before dawn. This is a fairly big event for southern hemisphere observers who might see up to one meteor a minute during tomorrow morning’s maximum. The radiant or point in the sky from which the meteors will appear to originate is much higher for southern latitudes. Morning twilight also begins later allowing for more viewing time.

The higher the radiant, the more meteors. A low radiant means most of a shower’s meteors are out of view, streaking away below the horizon. At latitude 50 degrees north the viewing window lasts 1 1/2 hours with the radiant low in the southeastern sky; at 40 degrees north, it’s a little more than 2 hours. If you live in the southern U.S. you’ll have nearly 3 hours of viewing time with the radiant 35 degrees high.

Shower meteors are typically small bits of rock or dust left behind by a comet. When the material hits the atmosphere, it heats the air to glow and we see a meteor.

Across the middle north latitudes expect to see about 10 very fast meteors an hour. Eta Aquarids, which are the dusty remains of numerous visits of Halley’s Comet to the inner solar system, tear across the sky at over 147,000 mph (237,000 km/hr). Slower meteors are often yellow or orange; these will flare white as they’re incinerated by the atmosphere.

Earth crosses Halley’s orbit twice a year. Each time, bits of the comet collide with our atmosphere and burn up. In mid-October we’ll encounter Halley’s orbit again and re-visit the comet’s dust trail as the Orionid meteor shower.

Tomorrow morning the crescent moon will also be out – it eases up over the tree line about the time dawn begins – and a special guest, Comet Lemmon, located about one “fist” to the moon’s left. While visible in binoculars as a dim, fuzzy patch of light, a telescope should show the comet’s bright head and diffuse tail. The radiant is located near the star Eta Aquarii well to the right of the familiar Great Square of Pegasus.

Halley’s Comet – source or parent of both the Eta Aquarid and Orionid meteor showers. Credit: NASA

Meteor shower members can appear in any part of the sky, but if you trace their paths in reverse, they’ll all point back to the radiant. Other random meteors you might see are called sporadics and not related to the Eta Aquarids.

For most mid-northern sky watchers, the best time to watch will be about 2 1/2-3 hours before sunrise. (Find your sunrise time HERE). Even if Aquarius is very low or hasn’t risen yet, you can still catch a few meteors before twilight brightens the sky. You might even get lucky and spot an Earth-grazer, a slow-moving meteor skimming the upper atmosphere nearly parallel to the ground. They’re best seen around the time the radiant rises. Keep an eye out for them.

The Eta Aquarid shower has a broad peak, so if it’s cloudy tomorrow, try again on Monday or Tuesday. You’re likely to catch at least a few. All you need for equipment are your eyes, a comfy lawnchair and a reasonably dark sky. Face east or south for the best view. Good luck!

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About astrobob

My name is Bob King and I work at the Duluth News Tribune in Duluth, Minn. as a photographer and photo editor. I'm also an amateur astronomer and have been keen on the sky since age 11. My modest credentials include membership in the American Association of Variable Star Observers (AAVSO) where I'm a regular contributor, International Meteorite Collectors Assn. and Arrowhead Astronomical Society. I also teach community education astronomy classes at our local planetarium.

3 thoughts on “Eta Aquarid meteor shower from Halley’s Comet peaks this weekend

  1. Bob,
    When these particles get separated from Hailey’s comet (or any comet), do they continue to travel along the orbit of the comet at a lower rate of speed? Or do they simply get suspended in place out in space?

    If they continue to travel, wouldn’t the change is mass and speed of the object also change the orbit?

    If they get suspended in place, why doesn’t the gravity of the sun just “suck” them all in?

    Thanks!
    RC

    • RC,
      Yes, they continue traveling along Halley’s orbit at least for a time until they’re either swept up by Earth (or other planets) or – depending upon mass – ejected from the solar system by radiation pressure from the sun or eventually spiral in toward the sun due to the Poynting-Robertson Effect (http://en.wikipedia.org/wiki/Poynting%E2%80%93Robertson_effect). It takes several thousand years for a typical particle 1 A.U. from the sun to fall into the sun.
      Since the particles are always moving – they once partook in Halley’s speed at the time they were deposited – they’re never still in space. The sun’s gravity and radiation pressure (Poynting-Robertson Effect again) do alter their velocities over time. The stream of Halley dust is replenished by that comet’s visits to the inner solar system every 76 years. Multiple encounters with planets can disperse a meteor stream (shower) and break it up into random or sporadic meteors. I hope this helps at least in part to answer your questions.

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