Early October Draconid Meteor Shower Has Radiant in Draco the Dragon

Summary: The early October Draconid meteor shower has its radiant in Draco the Dragon and peaks in 2015 between Thursday, Oct. 8, and Friday, Oct. 9.

Draconid meteor shower viewed from Fornelos de Montes, southwestern Galicia, northwestern Spain, in 2011, an outburst year with a display of 600+ meteors per hour: Contando Estrelas, CC BY SA 2.0 Generic, via Flickr

The Draconid meteor shower is predictable in its occurrence in the northwestern skies over Canada, the United States, Europe and northern Asia in early October, from the 6th to the 10th.

The shower’s unpredictability lies in its display. Known as an occasional shower, the Draconids either dazzle with a rare outburst of hundreds or thousands of meteors per hour or demand careful watching with sedate displays maximizing at languid rates of 1 to 20 per hour.

Peak viewing in 2015 is slated for the evening of Thursday, Oct. 8, and Friday, Oct. 9. The number of meteors flaring in an hour of peak activity, known as the zenithal hourly rate, is expected to maximize at about 10 per hour on the night of Oct. 8 and into the early morning hours of Oct. 9.

A waning crescent moon, with 18 percent visibility, yields a cooperative backdrop of sufficient darkness in clear skies for Thursday’s peaking shower. Friday’s crescent, waning at a slivery visibility of 11 percent, contends with cloudy, storming skies in the eastern United States while central and western states have clear skies for a slightly less dramatic continuation of Thursday’s peaks.

The Draconid meteor shower receives its name from its radiant, the point in the sky where the shower appears to originate. Draconids appear to radiate from the fiery mouth in the conspicuous asterism, or star pattern, of the four-star head of Draco the Dragon constellation. Draco's tail slithers between the Big Dipper, the seven-star asterism in Ursa Major ("Big Bear") constellation, and the Little Dipper, the seven-star asterism in Ursa Minor ("Little Bear") constellation.

Although a constellation of the far northern sky, Draco is viewable primarily in the Northern Hemisphere and minimally in the equatorial latitudes of the Southern Hemisphere. As a northern circumpolar constellation, Draco remains above the horizon throughout the night for latitudes north of the 35th parallel north, which in the United States defines Tennessee’s southern border.

Draco’s apparent meteor shower is a trail of debris sprayed by its parent, short periodic comet 21P/Giacobini-Zinner. The Draconids are also known as the Giacobinids in honor of French astronomer Michel Giacobini, who discovered the shower’s parent body over Nice in southeastern France on Dec. 20, 1900. The comet, which has an orbital period of 6.52 years, was recovered next by German astronomer Ernst Zinner over Bamberg in southeastern Germany on Oct. 23, 1913.

With brightness as a factor of size and speed, the Draconids’ slow movement, at a languorous pace of 6.8 miles (11 kilometers) per second, accounts for the meteor shower’s faintness. The temperamental Draconids’ exuberantly conspicuous 20th-century outbursts in 1933, 1946 and 2011 were precipitated by Earth’s passage through a dense part of Comet Giacobini-Zinner’s tail.

Although no fireworks are anticipated for 2015, the Draconids are always worth the watch because viewers do not have to maintain a vigil into the wee hours after midnight. Unlike the after-midnight best visibility of most meteor showers, the Draconids offer best viewing between nightfall, when Draco is at its zenith, or highest point, and midnight.

The only way to know whether Draconid meteor showers will flare abundantly or streak sedately in 2015 is to go outside, breathe nightfall’s fresh air and look to the northwest.

Draco the Dragon coiling around Ursa Minor (Little Bear constellation); ca. 1824 depiction by British cartographer and engraver Sidney Hall (1788–1831): Library of Congress Prints and Photographs, Public Domain, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Draconid meteor shower viewed from Fornelos de Montes, southwestern Galicia, northwestern Spain, in 2011, an outburst year with a display of 600+ meteors per hour: Contando Estrelas, CC BY SA 2.0 Generic, via Flickr @ https://www.flickr.com/photos/elentir/6223921931/

Draco the Dragon coiling around Ursa Minor (Little Bear constellation); ca. 1824 illustraton by British cartographer and engraver Sidney Hall (1788–1831) in Urania's Mirror (1825), plate 1; Library of Congress Prints and Photographs Division Washington, D.C.: Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Sidney_Hall_-_Urania's_Mirror_-_Draco_and_Ursa_Minor.jpg;
No known restrictions on publication in the U.S., via Library of Congress Prints & Photographs Online Catalog (PPOC) @ https://www.loc.gov/pictures/item/2002695394/

For further information:

“Draconid Meteor Shower Peaks October 8.” NASA Blogs > Watch the Skies. Oct. 8, 2015.
Available @ https://blogs.nasa.gov/Watch_the_Skies/2015/10/08/draconid-meteor-shower-peaks-october-8/

Kronk, Gary W. “Draconids.” Meteor Shows Online > Showers.
Available @ http://meteorshowersonline.com/

McClure, Bruce, and Deborah Byrd. “EarthSky’s meteor shower guide for 2015.” EarthSky > Tonight > Astronomy Essentials > Space. Oct. 6, 2015.
Available @ http://earthsky.org/astronomy-essentials/earthskys-meteor-shower-guide

McClure, Bruce, and Deborah Byrd. “Everything you need to know: Draconid meteor shower.” EarthSky > Tonight > Astronomy Essentials. Oct. 9, 2015.
Available @ http://earthsky.org/astronomy-essentials/everything-you-need-to-know-draconid-meteor-shower