Jenniskens和Vaubaillon发布在布拉格国际天文学大会会刊上，关于御夫座流星暴的文章
叶 泉志 发表于2006年8月20日10时34分
With the past Leonid storms still fresh in memory, the Earth is about to encounter another comet dust trail, which should shower the western USA and northern Pacific with a rain of meteors on September 1, 2007. This time, the comet is of the long-period type, orbiting the Sun only once every ~ 2000 years. When it last past Earth’s orbit in 82 BC, dictator Lucius Cornelius Sulla took control of Rome and a young Julius Ceasar was still only his subordinate in the East. In that year, the comet lost a cloud of dust particles. Since, it has taken some particles longer to return than others and a trail of dust is now passing Earth orbit constantly. Only when the planets steer of that trail and into Earth’s path
do we get to see a meteor outburst.
We predict that the Earth will encounter the 1-revolution dust trail of the long-period comet C/1911 N1 (Kiess) on September 1, 2007. A two-hour meteor outburst of “alpha-Aurigids” will occur with many +1 and +0 magnitude meteors. The encounter will peak at 11:37 UT, which makes the shower visible from the western United States, where the radiant will be high in the sky just before dawn. The Moon will be only three days before full Moon (on Sept. 04 at 02:32 UT) and high in the sky (~ 69° at San Francisco), but the typical Aurigid meteor will be so bright that the Moon won’t dim much of the display.
What makes this shower so special is the opportunity to see bits and pieces of the comet’s original crust. Long-period comets have just recently returned from cold storage in the Oort cloud and are still covered by a crust that resulted from 4.5 billion years of exposure to cosmic rays. When the comet returns to the inner solar system, that crust is crumbled and creates peculiar meteors.
The only other time that the dust trail of a long-period comet was investigated, during the 1995 alpha-Monocerotid outburst, it was found that the meteoroids had lost all of their volatile sodium minerals.
We can not be certain that the dust of comet Kiess is also from its original crust, but we better grab this opportunity. There will be no other chance to study long-period comet dust trails in the next three decades. More information on the prediction of meteor outbursts and the parent bodies of meteor showers can be found in the book “Meteor Showers and their Parent Comets” by Cambridge University Press, scheduled to arrive from the printer on August 16. Contact information: [email protected]
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