(NASA) The Earth is headed for a close encounter with the orbit of a newly discovered comet. Found by the Lincoln Near-Earth Asteroid Research (LINEAR) team on May 12th, Comet LINEAR (C/1999 J3) brightened to 9th magnitude as it made its closest approach to the Sun in September. On November 11, 1999 at 1941 UT, Earth will arrive at a point in space just 0.0115 AU from the orbit of the comet, 40 days after the comet itself was in the area. If there is a residual swarm of dusty debris left over from the comet's passage, we could be in for an unexpected meteor outburst -- the first known apparition of the 'Linearids.'

The International Meteor Organization (IMO) has issued a call for meteor observations during a 48 hour period centered on November 11. Linearid meteors -- if they materialize -- will appear to emanate from the bowl of the Big Dipper. The shower's radiant will be near right ascension 11h40m and declination +53 degrees.
 
LINEAR C/1999J3 is a long period comet. The most recent orbital elements indicate that it returns to the inner solar system only once every 63,000 years. All of the well-known annual meteor showers such as the Perseids and Leonids are produced by comets with much shorter periods. Short period comets pass by the sun over and over, building up a substantial cloud of dusty debris that causes meteor activity when the Earth passes close to the comet's orbit. For example, Comet Tempel-Tuttle -- the parent of the Leonid meteor shower -- has a period of only 33 years. Comet LINEAR has such a long period that dust ejected during close passes by the Sun probably dissipates before the comet returns to the vicinity of Earth. If this is the case, November 11 may not herald a particularly impressive shower.