Lyrids

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Lyrids (LYR)
Parent body C/1861 G1 (Thatcher)[1]
Radiant
Constellation Lyra
Right ascension 18h 08m[2]
Declination +32°[2]
Properties
Occurs during April 19 – April 25[2]
Date of peak April 22[2]
Velocity 48[3] km/s
Zenithal hourly rate 10[2]

See also: List of meteor showers
Radiant point of Lyrid meteor shower, active each year around April 22

The Lyrids (LYR) are a meteor shower lasting from April 16 to April 26[4] 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); hence they are also called the Alpha Lyrids and sometimes the April Lyrids. Their peak is typically around April 22 each year. The source of the meteor shower is particles of dust shed in the cometary tail generated by the periodic Comet C/1861 G1 Thatcher.[1] The Lyrids have been observed for the past 2600 years.[1]

The shower on May 22,[5] 687 BC (proleptic Julian calendar) was recorded in Zuo Zhuan, which describes the shower as "On day xīn-mǎo of month 4 in the summer (of year 7 of King Zhuang of Lu), at night, fixed stars are invisible, at midnight, stars dropped down like rain."[6] (夏四月辛卯 夜 恆星不見 夜中 星隕如雨)

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 ten.[4] As a result of light pollution, observers in the country will see more, observers in the city fewer. Nights without a moon in the sky will reveal the most meteors.

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.[7]

Occasionally, the shower intensifies when the Earth passes through a thicker part of the dust trail, resulting in a Lyrid meteor storm. In 1982, amateur astronomers counted 90 Lyrids per hour. A stronger storm of up to 700 per hour occurred in 1803,[3] 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 ..."[7]

Year Lyrids active between Peak of shower ZHRmax
2007 April 16–25 April 23 21[8]
2008 waning gibbous Moon (Full moon on April 20)[9]
2009 April 16–25 April 22 15[10]
2010 April 16–25 April 22 20[11]
2011 April 22 20[12]
2012 April 16–25 April 22 and April 26 (spiked to 37 ± 21) 25/37[13]
2013 April 16–25 April 22 (Full moon April 25)[14] 26[15]

2012 Bolide [edit]

Main article: Sutter's Mill meteorite

During the 2012 shower a bolide and sonic boom rattled buildings in California and Nevada around 8AM PDT 22 April 2012.[16] The bolide air burst was likely a random unrelated meteoroid and not a member of the Lyrids shower.[17] The bolide was so bright that witnesses were seeing spots afterward.[18] The event was recorded by two infrasound monitoring stations of the Comprehensive Nuclear-Test-Ban Treaty Organization’s International Monitoring System.[19] The preliminary analysis are indicative of energy yield of approximately 4 kilotons of TNT equivalent.[19] Hiroshima's "Little Boy" had a yield of about 15 kT. The meteoroid was likely between the size of a dish washer[20] and a mini van.[21] The air burst had approximate coordinates of 37.6N, 120.5W.[22] The meteor was picked up by weather radar between Auburn, CA and Placerville, CA.[23] Robert Ward found a small CM chondrite fragment in the Henningsen Lotus Park just west of Coloma, CA on 24 April 2012.[24] The meteorite fall is now known as the Sutter's Mill meteorite.[25]

A similar event was reported in northern Guatemala around 10:22PM 30 April 2012.[26]

Notes and references [edit]

  1. ^ a b c Arter, T. R.; Williams, I. P. (1997). "The mean orbit of the April Lyrids". Monthly Notices of the Royal Astronomical Society 289 (3): 721–728. Bibcode:1997MNRAS.289..721A. 
  2. ^ a b c d e Moore, Patrick; Rees, Robin (2011), Patrick Moore's Data Book of Astronomy (2nd ed.), Cambridge University Press, p. 275, ISBN 0521899354. 
  3. ^ a b Martinez, Patrick (1994), The Observer's Guide to Astronomy, Practical Astronomy Handbooks 2, Cambridge University Press, p. 645, ISBN 0521458986.  Unknown parameter |translator= ignored (help)
  4. ^ a b "Lyrids". Meteor Showers Online. p. 1. Retrieved 2008-08-05. 
  5. ^ Some sources claims it was March 16, which cannot be right. First, March 16 they claimed was actually in proleptic Gregorian calendar; Second, it was not in summer as original text have described clearly.
  6. ^ Sinnott, Roger W. (2008). "Meteors – April's Lyrid Meteor Shower". Sky and Telescope. p. 1. Retrieved 2008-08-05. 
  7. ^ a b "the Lyrid meteor shower". spaceweather.com. 2008. p. 1. Retrieved 2008-08-05. 
  8. ^ Lyrids 2007: visual data quicklook
  9. ^ U.S. Naval Observatory Phases of the Moon 2008
  10. ^ Lyrids 2009: visual data quicklook
  11. ^ Lyrids 2010: visual data quicklook
  12. ^ Lyrids 2011: visual data quicklook
  13. ^ "Lyrids 2012: visual data quicklook". International Meteor Organization. Retrieved 2012-04-26. 
  14. ^ U.S. Naval Observatory Phases of the Moon 2013
  15. ^ "Lyrids 2013: visual data quicklook". International Meteor Organization. Retrieved 2013-04-22. 
  16. ^ Guy Clifton (April 22, 2012). "Meteor shower likely cause of big boom heard throughout region". Reno Gazette-Journal. Retrieved 2012-04-22. 
  17. ^ Deborah Byrd (April 22, 2012). "Loud boom and bright fireball over California and Nevada on April 22". EarthSky. Retrieved 2012-04-22. 
  18. ^ Guy Clifton (April 23, 2012). "Local resident's photo of Sunday's meteor goes international". Reno Gazette-Journal. Retrieved 2012-04-23. 
  19. ^ a b Guy Clifton (April 23, 2012). "Scientist says sound signal from exploding meteor lasted 18 minutes". Reno Gazette-Journal. Retrieved 2012-04-23. 
  20. ^ "Explosion Heard in NV, CA Traced To Meteor". KTVN 2 (Reno). April 22, 2012. Retrieved 2012-04-23. 
  21. ^ "Fireball Over California/Nevada: How Big Was It?". NASA/JPL. April 24, 2012. Retrieved 2012-04-24. 
  22. ^ Bill Cooke of NASA Meteoroid Environments Office (April 23, 2012). "(meteorobs) Fwd: large bolide over California/Nevada". Retrieved 2012-04-23. 
  23. ^ Marc Fries (mfries01) (23 April 2012). "Coloma, CA 22 Apr 2012 1452 UTC". Radar Obs of Meteor Events. Retrieved 2012-04-25. 
  24. ^ Franck Marchis (Wed April 25, 2012). "Re: {MPML} Fireball Over California/Nevada: How Big Was It?". Yahoo group: Minor Planet Mailing List (mpml). Retrieved 2012-04-25. 
  25. ^ Franck Marchis (April 25, 2012). "Fragments of the daylight meteor found in California". Cosmic Diary. Retrieved 2012-04-26. 
  26. ^ "Meteorito es visto en espacio aéreo de Guatemala". elPeriodico. May 1, 2012. Retrieved 2012-05-01. 

External links [edit]
By name
By peak date
Related topics
For a complete list, see List of meteor showers
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