Draconid Meteor OutburstOct. 4, 2011: On October 8th Earth is going to plow through a stream of dust from Comet 21P/Giacobini-Zinner, and the result could be an outburst of Draconid meteors.
"We're predicting as many as 750 meteors per hour," says Bill Cooke of NASA's Meteoroid Environment Office. "The timing of the shower favors observers in the Middle East, north Africa and parts of Europe."
Comet 21P/Giacobini-Zinner in Nov. 1998 photographed by astronomers at Kitt Peak. [more]
"Most years, we pass through gaps between filaments, maybe just grazing one or two as we go by," says Cooke. "Occasionally, though, we hit one nearly head on--and the fireworks begin."
2011 could be such a year. Forecasters at NASA and elsewhere agree that Earth is heading for three or more filaments on October 8th. Multiple encounters should produce a series of variable outbursts beginning around 1600 Universal Time (noon EDT) with the strongest activity between 1900 and 2100 UT (3:00 pm – 5:00 pm EDT).
Forecasters aren't sure how strong the display will be, mainly because the comet had a close encounter with Jupiter in the late 1880s. At that time, the giant planet's gravitational pull altered the comet's orbit and introduced some uncertainty into the location of filaments it has shed since then. Competing models place the filaments in slightly different spots; as a result, estimated meteor rates range from dozens to hundreds per hour.
Comet dust stream models suggest a succession of peaks in meteor rate between 1600 and 2100 UT on Oct. 9th. Click here for details. Credit: MSFC/Meteoroid Environment Office.
"A Draconid gliding leisurely across the sky is a beautiful sight," says Cooke.
Unfortunately, many of this year's Draconids will go unseen. Draconids are faint to begin with, and this year they have to complete with an almost-full Moon. Lunar glare will reduce the number of meteors visible from Europe, Africa and the Middle East by 2- to 10-fold. The situation is even worse in North America where the shower occurs in broad daylight—completely obliterating the display.
That isn't stopping a group1 of middle school and high school students from Bishop, California, however. They plan to observe the shower from the stratosphere where the sky is dark even at noontime.
Black skies at high noon, photographed from a high-altitude helium balloon on Sept. 3, 2011. Credit: Earth to Sky, a student group located in Bishop, CA.
"The students are going to attempt to fly one of our low-light meteor cameras in the payload of their balloon," says Cooke. "I hope they catch some Draconid fireballs for us to analyze. They could be the only ones we get."
Stay tuned for results after Oct. 8th.
Author: Dr. Tony Phillips | Credit: Science@NASA