Two Fireballs Sighted from Comet Hartley 2 -Do They Signal a New Meteor Shower Display?

1013885main_meteor_color Astronomers have recorded sightings of two fireballs that may have come from Comet Hartley 2 that made its closest pass by Earth in 24 years this month, prompting speculation on whether the icy cosmic interloper may have a trailing a meteor shower show.

The fireballs were spotted on Oct. 16, just four days before the close pass by Comet Hartley 2 and a few weeks ahead of a Nov. 4 visit to the comet by NASA spacecraft Deep Impact. It is possible that the fireballs are related to the comet, but it may also be a coincidence, NASA scientists said.

But NASA scientists were skeptical of any meteor display from Comet Hartley 2. "Probably not," said astronomer Bill Cooke, head of NASA's Meteoroid Environment Office, "but the other night we saw something that makes me wonder" referring to the twin fireballs, which were spotted five hours apart on the night of Oct. 16 by skywatching cameras in Canada and the United States.

The Canadian fireball was first and spotted by all-sky cameras operated by the University of Western Ontario as it streaked over eastern Canada. The fireball over the U.S. was a slow, bright meteor that passed over Alabama and Georgia. Multiple cameras recorded the displays of each fireball, which allowed astronomers to calculate the orbits of both objects before they struck Earth's atmosphere.

"The orbits of the two fireballs were very similar," Cooke said in a statement. "It's as if they came from a common parent." The orbits of the two fireballs were roughly similar to the Comet Hartley 2, NASA officials said. But Cooke cautioned."Thousands of meteoroids hit Earth's atmosphere every night," he said. "Some of them are bound to look like 'Hartley-ids' just by pure chance."

Cooke plans to keep watching for possible meteors, especially on Nov. 2 and Nov. 3 when the show is expected to be the strongest. Hartley 2 "has been sputtering space dust for thousands of years, making a cloud that is much bigger than the comet itself," Cooke said. "Solar radiation pressure and planetary encounters cause the comet and the dust cloud to divergeot a lot, but enough to make the date of the shower different from the date of the comet's closest approach."

The October Orionid meteor shower and May Aquarid shower, for example, are the remnants of the famed Halley's Comet. The Taurid meteor shower, which peaks between mid-October and mid-November, is caused by the cosmic detritus of Comet Encke.

Any meteors from Comet Hartley 2 would likely appear in the the constellation of Cygnus, the Swan, which is visible directly overhead to skywatchers in the Northern Hemisphere after sunset. Moonlight should not obscure the potential sky show since it will be only a slender crescent at the time, NASA officials said.

"I'll definitely have our cameras turned on," Cooke said of the possible Hartley 2 meteor peak time. "It's probably going to be a non-event. On the other hand, we might discover a whole new meteor shower."


Jason McManus via NASA News. Comet Hartley 2 shown above. Amateur astronomer Rolando Ligustri took this picture on Oct. 1st using a 14-inch Global Rent-a-Scope in New Mexico. It shows Comet Hartley beside the spectacular Pacman Nebula (NGC 281), a star-forming cloud some ten thousand light years from Earth.


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