Finally! In the magazine, WGN (Journal of the International Meteor Organization) is our article Geminids, 30 years of observations (1980-2009) was published. I am very proud of this article and have wrote it together with my good friends Carl Johannink, Michel Vandeputte and Peter Bus.
Hopefully, we can write a sequel to this article, with additions from 2010 and more importantly this year (2012) to see if we have the cautious conclusions from the article to confirm or not.
A Dutch language version of this article was previously published in the journal eRadiant 2010-6. This is a free download via the DMS website: www.dmsweb.org
Geminids: 30 years of observations (1980-2009)
Koen Miskotte, Carl Johannink, Michel Vandeputte and Peter Bus
Among active meteor observers the Geminid meteor stream is known as the most reliable shower that can be observed. The activity period occurs mid December which has both advantages and disadvantages. The fact that winter nights are long and that the stream can be observed all night long is an advantage. During a crystal clear night of 13-14 December, depending upon the perception of the observer, observing conditions and duration, one can count hundreds if not more as thousand meteors. However, the unreliability of the weather especially in Western Europe in December is a disadvantage: In the Netherlands there is less than 10% chance for a clear night while at more favorable locations such as Spain or Portugal this percentage is still only 50%.
The most interesting for the Geminids is that the stream was discovered in the 19th century and gradually became more active. Past decades the Geminid displays became one of the most active annual showers and scientists wonder whether or not this evolution will continue to increase or rather stabilize or decrease. Some researchers concluded that the highest level was achieved around the year 2000, but there are other theories which predict further increasing hourly rates for the next decades. Peter Jenniskens (2006) suggests that the highest hourly rates will occur around 2050 and the ratio of bright Geminids will increase significantly.
In recent years the Geminids peak with a ZHR of ~120-140 meteors an hour. This is more than an usual Perseid return (ZHR of 80). That the activity is actually still increasing or decreasing is a question that requires a good dataset for a long period of time. Just like in climatology conclusions will be possible on basis of many years of intensive observing efforts and this preferably by the same observers.
The Dutch Meteor Society is active since 1979 and in a number of years the Geminids could be very well observed. The evolution of the Geminid activity is rather slow but in a time interval of 30 years some indication of this evolution may have been recorded? In this article we consider an overview of the Geminid activity between 1983 and 2009 and we attempt to verify if any of the proposed models can be supported with our data. With other words, is there anything of this predicted evolution reflected in our data?