Saturday, August 04, 2012

Perseid Fireballs Through August 3rd

The above chart shows the number of Perseid fireballs recorded through August 3rd by the eight cameras of NASA's All Sky Fireball Network (fireballs.ndc.nasa.gov). Image Credit: James M. Thomas

We've been hearing reports of fireballs from the 2012 Perseid meteor shower, which runs from July 23rd through August 20th with a maximum over August 11th/12th. To put the reports in perspective, we thought we would use the data gathered from NASA's All Sky Fireball Network, which is part of NASA's Meteoroid Environment Office.

Please remember that the Network currently has only eight video cameras, with two in New Mexico and the rest spread over Alabama, Georgia and South Carolina. That being said, the data is interesting. From July 26th through August 3rd, at least one Perseid fireball has been seen each night. And over this nine-day period, the Perseid fireballs observed average 3.67 per night. For these observations, a fireball is defined as any meteor with a brightness equal to Venus or brighter.

Perseids enter the atmosphere at about 59 km/second (37 miles/second) and are yellow in color. The Perseid shower occurs each year when Earth passes through the debris trail of Periodic Comet 109P/Swift-Tuttle, also called Comet 1862 III, discovered on July 16, 1862 by American astronomer Lewis A. Swift and then independently discovered three days later by American astronomer Horace Parnell Tuttle. Perseid meteors appear to radiate from a point in the constellation of Perseus (Right Ascension 03hrs 04min, Declination +58°). This year, the zenithal hourly rate is expected to reach 60.

We still have about ten days until the Perseid maximum on August 13th. We look forward to what this shower has in store for us in the coming days.

To learn more about meteors, comets, and asteroids, check out these URLs.

NASA's All Fireball Network (fireballs.ndc.nasa.gov), part of NASA's Meteoroid Environment Office, www.nasa.gov/offices/meo .

Asteroids, Comets, Meteorites (a NASA Asteroid Watch article): www.jpl.nasa.gov/asteroidwatch/asteroids-comets.cfm

NASA's Near-Earth Object (NEO) Program coordinates NASA-sponsored efforts to detect, track and characterize potentially hazardous asteroids and comets that could approach the Earth. To learn more, visit the home page of NASA's Near-Earth Object Program: neo.jpl.nasa.gov .

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