May’s Eta Aquarid meteor shower hails from Halley’s Comet

The Eta Aquarid meteor shower is active in early May and peaks before dawn on Tuesday and Wednesday May 6-7 this year. Watch for it before the start of morning twilight in the eastern sky. Created with Stellarium

Active right now but peaking on Tuesday and Wednesday mornings May 6-7, the annual Eta Aquarid meteor shower likewise peaks our interest in its origin. Most showers trace their parentage to a particular comet. The Perseids of August originate from dust strewn along the orbit of comet 109P/Swift-Tuttle, which drops by the inner solar system every 133 years after “wintering” for decades just beyond the orbit of Pluto.

Halley’s Comet photographed in May 1986 during its last go-round the sun. Dust particles boiled off the comet when near the sun are left behind in its orbit. Every May, Earth encounters the stream and we see the Eta Aquarid meteor shower. Halley’s next approach to Earth happens in the summer of 2061. Credit: Bob King

The upcoming Eta Aquarids (AY-tuh ah-QWAR-ids) have the best known and arguably most famous parent of all: Halley’s Comet. Twice each year, Earth’s orbital path intersects dust and minute rock particles strewn by Halley during its cyclic 76-year journey from just beyond Uranus to within the orbit of Venus.

Our first pass through Halley’s remains happens this week, the second in late October during  the Orionid meteor shower. Like bugs hitting a windshield, the grains meet their demise when they smack the atmosphere at 42 miles per second (68 km/sec) and fire up for a brief moment as meteors.

The farther south you live, the higher the shower radiant will appear in the sky and the more meteors you’ll see. For southern hemisphere observers this is one of the better showers of the year with rates around 30-40 meteors per hour. No moon mars the view, making conditions ideal.

Vintage painting of a fireball meteor flashing across the sky. While the Eta Aquarids aren’t known for their fireballs, the meteors are swift and white.

From mid-northern latitudes the radiant or point in the sky from which the meteors will appear to originate is low in the southeast before dawn. At latitude 50 degrees north the viewing window lasts about 1 1/2 hours; 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.

Expect to see 5-10 meteors per hour during the hour or two before the start of dawn Wednesday May 7. Face east for the best view and relax in a reclining chair. An added bonus this spring season will be hearing the first birdsong as the sky brightens toward the end of your viewing session.

A modern photographic depiction of Eta Aquarid meteors from May 2012. Credit: John Chumack

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. Meteor showers take on the name of the constellation from which they originate.

Aquarius sports at least two showers. This one’s called the Eta Aquarids because it emanates from near the star Eta Aquarii. An unrelated shower, the Delta Aquarids, is active in July and early August.

Happy viewing and clear skies!

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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.

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