Geminids

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Geminids (GEM)
Comet holmes and Geminid121307.jpg
Geminid (left) and comet 17P/Holmes (lower right)
Discovery date 1862[1]
Parent body 3200 Phaethon[2]
Radiant
Constellation Gemini (near Castor)
Right ascension 07h 28m[2]
Declination +32°[2]
Properties
Occurs during December 7 – December 17[2]
Date of peak December 14[2]
Velocity 35[3] km/s
Zenithal hourly rate 75+[2]
See also: List of meteor showers

The Geminids are a meteor shower caused by the object 3200 Phaethon,[4] which is thought to be a Palladian asteroid[5] with a "rock comet" orbit.[6] This would make the Geminids, together with the Quadrantids, the only major meteor showers not originating from a comet. The meteors from this shower are slow moving, can be seen in December and usually peak around December 13–14, with the date of highest intensity being the morning of December 14. The shower is thought to be intensifying every year and recent showers have seen 120–160 meteors per hour under optimal conditions, generally around 02:00 to 03:00 local time. Geminids were first observed in 1862,[1] much more recently than other showers such as the Perseids (36 AD) and Leonids (902 AD).

Radiant[edit]

Geminids Meteor Shower in northern hemisphere
A Geminid meteor in 2009, seen from San Francisco
Asteroid (3200) Phaethon, parent body of the Geminids, imaged on December 25, 2010 with the 37 cm F14 Cassegrain telescope of Winer Observatory, Sonoita (MPC 857)

The meteors in this shower appear to come from a radiant in the constellation Gemini (hence the shower's name). However, they can appear almost anywhere in the night sky, and often appear yellowish in hue. Well north of the equator, the radiant rises about sunset, reaching a usable elevation from the local evening hours onwards. In the southern hemisphere, the radiant appears only around local midnight or so. Observers in the northern hemisphere will see higher Geminid rates as the radiant is higher in the sky.[7] The meteors travel at medium speed in relation to other showers, at about 22 miles per second, making them fairly easy to spot. The Geminids are now considered by many to be the most consistent and active annual shower. Geminids disintegrate while at heights above 38 kilometres (24 mi).[8]

Short animation of single Geminids meteor falling earthwards
Year Active Peak of shower ZHRmax Lunar phase
2006 December 7–17 December 14 115[9] 33% waning crescent
2007 December 15 122[10] 28% waxing crescent
2008 December 14 139[11] 96% Full moon
2009 December 13 120[12] 10% new moon
2010 December 7–17 December 14 127[13] 57% first quarter
2011 December 14 198[14] 86% waning gibbous
2012 December 4–17[3] December 13–14[3] 109[15] 1% new moon
2013 December 4–17[16] December 14 (predicted ZHR=120)[16] 134[15] 91% Full moon

≈ Predicted Zenithal Hourly Rate (ZHR)

See also[edit]

References[edit]

  1. ^ a b Gary W. Kronk. "Observing the Geminids". Meteor Showers Online. Retrieved 2012-11-14. 
  2. ^ a b c d e f Moore, Patrick; Rees, Robin (2011), Patrick Moore's Data Book of Astronomy (2nd ed.), Cambridge University Press, p. 275, ISBN 0-521-89935-4. 
  3. ^ a b c "IMO Meteor Shower Calendar 2012: Geminids (GEM)". International Meteor Organization. Retrieved 2012-12-13. 
  4. ^ Brian G. Marsden (1983-10-25). "IAUC 3881: 1983 TB AND THE GEMINID METEORS; 1983 SA; KR Aur (Circular No. 3881)". Central Bureau for Astronomical Telegrams. Retrieved 2009-05-18. 
  5. ^ Victoria Jaggard (2010-10-12). "Exploding Clays Drive Geminids Sky Show?". National Geographic Society. Retrieved 2010-10-18. 
  6. ^ Jewitt, David; Li, Jing (2010). "Activity in Geminid Parent (3200) Phaethon". arXiv:1009.2710 [astro-ph.EP].
  7. ^ "Radiant (Northern vs Southern)". NASA Meteor Watch on Facebook. 2012-12-12. Retrieved 2012-12-14. 
  8. ^ "NASA All Sky Fireball Network: Geminid End Heights". NASA Meteor Watch on Facebook. 2012-12-11. Retrieved 2012-12-11. 
  9. ^ "Geminids 2006: visual data quicklook". International Meteor Organization. 2007-04-25. Retrieved 2012-12-13. 
  10. ^ "Geminids 2007: visual data quicklook". International Meteor Organization. 2008-08-10. Retrieved 2012-12-13. 
  11. ^ "Geminids 2008: visual data quicklook". International Meteor Organization. 2009-01-02. Retrieved 2012-12-13. 
  12. ^ "Geminids 2009: visual data quicklook". International Meteor Organization. 2010-04-19. Retrieved 2012-12-13. 
  13. ^ "Geminids 2010: visual data quicklook". International Meteor Organization. 2012-09-19. Retrieved 2012-12-13. 
  14. ^ "Geminids 2011: visual data quicklook". International Meteor Organization. 2012-01-18. Retrieved 2012-12-13. 
  15. ^ a b "Geminids 2012: visual data quicklook". International Meteor Organization. 2012-12-21. Retrieved 2013-10-11. 
  16. ^ a b "IMO Meteor Shower Calendar 2013: Geminids (GEM)". International Meteor Organization. Retrieved 2013-10-11. 

External links[edit]