Geminids

Geminids (GEM)
200px Geminid meteor shower over the Iranian desert
Discovery date	1862
Parent body	3200 Phaethon
Radiant
Constellation	Gemini (near Castor)
Right ascension	07h 28m
Declination	+32°
Properties
Occurs during	December 7 – December 17
Date of peak	December 14
Velocity	35 km/s
Zenithal hourly rate	75+

The Geminids are a meteor shower caused by the object 3200 Phaethon, which is thought to be a Palladian asteroid with a "rock comet" orbit. 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, much more recently than other showers such as the Perseids (36 AD) and Leonids (902 AD).

Radiant

File:Geminids.jpg

Geminids Meteor Shower in northern hemisphere

File:Geminid 121407 1.jpg

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. 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).

Short animation of single Geminid meteor falling earthwards

Year	Active	Peak of shower	ZHRmax	Lunar phase
2006	December 7–17	December 14	115	33% waning crescent
2007		December 15	122	28% waxing crescent
2008		December 14	139	96% Full moon
2009		December 13	120	10% new moon
2010	December 7–17	December 14	127	57% first quarter
2011		December 14	198	86% waning gibbous
2012	December 4–17	December 13–14	109	1% new moon
2013	December 4–17	December 14	134	91% Full moon
2014	December 4–17	December 14	253	50% Last Quarter

See also

• List of meteor showers

External links

• Viewing details for the 2015 Geminids Meteor Shower
• Viewing information for the 2015 Geminids meteor shower
• NASA Meteor Watch 2012:
  • Allsky cameras observed 328 bright Geminids - notice how similar they are to the orbit of the asteroid 3200 Phaethon (purple orbit)
  • Composite view of meteors detected in the skies over Marshall Space Flight Center (MSFC)
  • Spectacular Geminid, brighter than the Full Moon (video 2012-Dec-14 07:28 UT)
  • Meteoroid Environment Office: 53 meteor orbits last night of which 18 were Geminids
• NASA meteor flux estimator (Leonid MAC Meteor Shower Estimator)
• 2004 Geminids
• 2006 Geminids
• ShadowandSubstance.com: Geminids animated for 2010
• "Weird Geminids," NASA, 7 December 2001
• Google group search for Geminids, sorted by date
• Amateur observations of the Geminids
• Triangulation of a Geminid Meteor by Crayford Manor House AS
• ScienceCasts: Rock Comet Meteor Shower (Science@NASA YouTube channel : Nov 29, 2012)
• Geminids at Constellation Guide

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