Lyrids
| April Lyrids (LYR) | |
|---|---|
| Parent body | C/1861 G1 (Thatcher) |
| Radiant | |
| Constellation | Lyra |
| Right ascension | 18h 08m |
| Declination | +32° |
| Properties | |
| Occurs during | April 19 – April 25 |
| Date of peak | April 22 |
| Velocity | 48 km/s |
| Zenithal hourly rate | 10 /hr |
The April Lyrids (LYR, IAU shower number 6 ) are a meteor shower lasting from April 16 to April 26 each year. The radiant of the meteor shower is located in the constellation Lyra, near this constellation's brightest star, Alpha Lyrae (proper name Vega). Their peak is typically around April 22 each year.
The source of the meteor shower is particles of dust shed by the long-period Comet C/1861 G1 Thatcher. The April Lyrids are the strongest annual shower of meteors from debris of a long-period comet, mainly because as far as other intermediate long-period comets go (200–10,000 years), this one has a relatively short orbital period of about 415 years. The Lyrids have been observed for the past 2,600 years.
The shower usually peaks on around April 22 and the morning of April 23. Counts typically range from 5 to 20 meteors per hour, averaging around 10. As a result of light pollution, observers in rural areas will see more than observers in a city. Nights without a moon in the sky will reveal the most meteors. April Lyrid meteors are usually around magnitude +2. However, some meteors can be brighter, known as "Lyrid fireballs", cast shadows for a split second and leave behind smokey debris trails that last minutes.
Occasionally, the shower intensifies when the planets steer the one-revolution dust trail of the comet into Earth's path, an event that happens about once every 60 years. This results in an April Lyrid meteor outburst. The one-revolution dust trail is dust that has completed one orbit: the stream of dust released in the return of the comet prior to the current 1862 return.This mechanism replaces earlier ideas that the outbursts were due to a cloud of dust moving in a 60-year orbit. In 1982, amateur astronomers counted 90 April Lyrids per hour at the peak and similar rates were seen in 1922. A stronger storm of up to 700 per hour occurred in 1803, observed by a journalist in Richmond, Virginia:
"Shooting stars. This electrical [sic] phenomenon was observed on Wednesday morning last at Richmond and its vicinity, in a manner that alarmed many, and astonished every person that beheld it. From one until three in the morning, those starry meteors seemed to fall from every point in the heavens, in such numbers as to resemble a shower of sky rockets ..."
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