The Leonids Meteor Shower

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Meteors are the result of dust size particles hitting the earth’s atmosphere at speeds of about 40 miles per second and burning up leaving trails of superheated air after them.

Meteors cannot reach the earth, they burn up at about 50 miles altitude.

The Leonids meteor shower, which occurs around mid November, is caused by debris left in the wake of comet 55P Tempel/Tuttle and we normally see no more than about 10 meteors per hour.

The meteors in the case of this meteor shower seem to radiate from the constellation of Leo hence the name Leonids.

Almost half of all meteor storms reported during the last 1000 years are associated with the Leonids.

Comets are dirty snowballs, left after the formation of the Solar System, which reside well outside the orbit of Jupiter in the Ort Cloud.

Some of these Comets are thought be dislodged by the massive gravitational forces of Jupiter. The comets in turn are captured by the Sun’s gravity and hurtle around it heading back deep into the depths of the Solar system to return again after a period of years.

Comets eventually crash into the sun or are dissolved by its heat as the orbit the Sun or are lost in space altogether.

The Leonids can be traced back to 902 ad and have appeared frequently after that.

In 1833 in Boston on the night of November 12-13^th the frequency of meteors was estimated to be about half that of flakes of snow in an average snowstorm, it was estimated that about ¼ million meteors must have been visible in the 9 hours that they continued to fall.

In 1866 Ernst Tempel and Horace Tuttle independently discovered the comet and it was found to have an orbit of about 33.3 years, a meteor storm for November of that year was predicted and in fact did happen.

In November 17^th 1966 tens of thousands of meteors fell in a short period of time in western USA.

The Leonids of 1994 was the first outburst of the new return of the comet for our generation, high Leonid rates measured in November 18^th, were as strong as that years Perseids.

Observations in 1995/1996 confirmed the enhanced rates.

In 1998 numerous fireballs with long lasting trails and a 2^nd peak associated with older dust trails were observed.

In 1999 the earth encountered one of these narrow dust trails, which was ejected from comet Temple/Tuttle in 1899!

In 2000 the predicted low rates of 100/hr still exceeded the Perseids (60/hr maximum predicted) for that year.

November 18^th 2001 saw 2 peaks about 8 hours apart.

2 astronomers working in Armagh Observatory feature prominently in very accurate predictions and time of arrival of this meteor shower, Robert Mc Naught & David Asher’s predictions are capable of being to within 6 minutes of the actual peak (November 1999)

When you consider that a team of German Amateurs are heading to the south west coast of Ireland to attempt a meteor scatter crossing on 144 mhz with German and Canadian hams on the other side of the Atlantic during the peak of this Leonids, it shows that it is generating great interest, a meteor storm will make 144mhz look as if there is a Sporadic-E opening, great distances and numerous contacts will be possible if this occurs.

Leonids 2002

This year it is predicted that the Leonids will have 2 peaks both well over 1000/hr. It is unfortunate that there will be a full moon this year, which will wipe out the weaker meteors.

Peaks are predicted for this side of the Atlantic at between 4-00 and 4-15 am on November 19^th with between 1000 and 3000/hr forecast The next peak is several hours later at between 10-15 and 10-45 am that morning with 3500/hr forecasted.

If you are going to be active in meteor scatter please get a report from a nearby station or stations before hand in case you are splattering.

Leonids 2002 will be our last chance to see them and they will not return until 2098 or 2131, because in the other years 2033, 2065 the separation of the dust trails from the earth will be too great.