"The Earth will not go through one of the highest density regions in the Leonid[s]," said David Asher, a Leonid expert at Ireland's Armagh Observatory. "There is no hard and fast rule of where the highest density regions are but one can say the densest regions are associated with younger trails."
On late Tuesday night and early Wednesday morning, astronomers expect Earth to intersect a stream of debris cooked off the Tempel-Tuttle in 1533. The meteors on November the 13 were from a stream cooked in 1499.
Faint or Bright?
While astronomers have improved the accuracy with which they predict when the Earth will intersect debris of comet Tempel-Tuttle that produces the Leonids, they are less sure in their predictions of how many meteors will be seen and how bright they will be.
The aid of newer, bigger, and faster computers has allowed astronomers to chart where and when Earth is likely to intersect a debris stream and correlate any particular debris stream (or trail) to the year it was cooked off Tempel-Tuttle by the sun.
"But the number of bright meteors and intensity requires knowing how particles are being ejected from the comet in more detail than we actually can do," said Cooke.
Asher said that the heavier particles tend to stay closer to the comet as the smaller particles are pushed further back by radiation pressure from the sun.
"The parts of the 1499 and 1533 trails that will be encountered by Earth this month are not the parts of those trails that contain the largest particles," he said. Since smaller particles produce fainter meteors, Asher expects this year's Leonids to be faint.
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