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Leonids 2005


(13th-21st November 2005)

By Salvador Ribas

General information:

The Leonids are one of the most characteristic meteor showers. They are given this name because they appear to radiate from the area of the sky occupied by Leo; that is, their radiant is situated there. It is necessary to remember that a meteor shower consists of lots of meteors (what we commonly call shooting stars) falling from the space into Earth's atmosphere.


(Image obtained by Gary W. Kronk using Sky Chart III 3.5 and Adobe Photoshop 5.5)
Approximate position of the radiant, for middle latitudes of northern hemisphere, at 2:00 a.m. local time for dates near the maximum (the middle of November). In order to know the dates and hours of maximums with accuracy to look predictions up is needed.

Meteors can be just like little dust specks or, the other way round, enormous rocky fragments. Terrestrial atmosphere are continuously receiving objects of this type, but concrete dates exist when the rate of arrival grows considerably and then it is said a meteor shower to go on. Meteors, when arrive to the atmosphere and move through it, are suddenly heated by friction and burn up giving rise to the amazing characteristic traces.

Most of the meteor showers have their origin in comets. These objects are made of ice and dust (that is why they are often called dirty snowballs) and when they arrive near the Sun, their iced parts partially evaporates and then dust is thrown out and can remain trapped in the orbit of the comet. Usually, the distribution of the dust through the orbit is not uniform. The comet which generates the Leonids is Tempel-Tuttle, that has a period of 33 years. When this comet pass near the Sun, it throws out part of its matter and considerably fills that area of the orbit with particles.

Every year, on 17th or 18th November, the Earth intercepts Tempel-Tuttle's orbit and fragments one day thrown out by the comet fall down through the atmosphere and a meteor shower occurs. If this interception takes place a short time after the comet has passed by (once every 33 years) the meteor shower is very intense. That is what we commonly call a "storm", when observing some thousands of shooting stars per hour is possible.

Ōrbita Tempel-Tuttle

(Image produced by Gary W. Kronk with the program Starry Night Pro 3.0)" hreflang="en">Tempel-Tuttle's orbit and also the orbit of the fragments that give raise to the Leonids.

On February 1998, Tempel-Tuttle visited the inner parts of the Solar System and as a result very intense meteor showers have taken place since that moment. For instance in 1999, 3700 shooting stars per hour were observed during the maximum, and in 2002 to count up to near 3000 per hour was possible in spite of the maximum coincided with a very brilliant full Moon.

IMO's report about the Leonids (2002)

The Leonids are usually fast meteors that can reach the top of the atmosphere with more than 200,000 km/h. Moreover, they usually have an important number of brilliant meteors, many of them being able to leave eye-catching trails which can be visible through some minutes.

Acknowledgements: Some images and data have been obtained from Gary W. Kronk's Comets & Meteor Showers.

2005 Forecast:

Predictions for this year 2005 are not specially good, because predictive mathematical models for the Leonids, as in past years 2003 and 2004, do not offer any intense meteor shower. Besides, the appearance of a nearly full Moon will difficult observations.

If Mikhail Maslov's predictions, based upon models by Lyytinen & Van Flandern, are considered the following intensity maximums are obtained:

  • A first maximum will occur on 17th November with a central top over 14:30 UT . This maximum is thought to be produced by the background of particles left behind by Tempel-Tuttle, so it is not a direct interception of a trace. As a result, the number of observable meteors will be quite little, about 15 per hour. People from Pacific and neighbourhood will have the best chance to observe this maximum. In particular, on the one hand,it will take place at 0:30 (early morning of 18th) in Vladivostock (Russia), 1:30 in Sidney, 3:30 in New Zealand and, on the other hand,because of the position of the line of changing date, it will be 4:30 (early morning of 17th) in Hawaii and 5:30 in Alaska.
  • The second interesting moment will occur on 21st November, with a maximum about 1:10 UT caused by the trace left behind by Tempel-Tuttle in 1167, so the number of observable meteors will be over 18 per hour. Because of this is a very ancient trace, it can be quite broad and as a result the maximum will probably last 20 hours, allowing the observation through the night from 20th to 21st nearly all over the world. Nevertheless, the same fact - being a so ancient trace - difficults predictions a lot and makes them not very reliable: meteor shower can be until 3 times more intese or nearly non-existent. That is the reason why taking data is an important activity for this maximum. If forecasts are correct, the top is very appropiate for Europe and Africa: it will be at 2:10 (early morning of 21st) in Spain, 3:10 in Egypt and 4:10 in Moscow.

For more details about time zones you can go to The World Clock

Images of the Leonids:

Send us your photographs to the mail !!! We will post them on this web page so that everybody can contemplate them.


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