The Meteor Train Observing Project

At the start of the '90s, Mark Vints set up an observing project for meteor trains [1]. Train observations became standardized and were put in a meteor database. In the first years a substantial number of observations were sent in, but after a while this decreased rapidly. Moreover, Mark couldn't devote much time to work on the project. That's why we have decided to give the project a second chance and we hope to get some useful results.

Why observe trains?

Meteor train data are neglected by a lot of observers. Since the project has been started, there is an improvement visible, but still most observers just mention when trains appear, sometimes with the train duration. In too few cases train observations were reported to the database. It is clear that lots of observations are needed, because of the rather low frequency of meteor trains.

There are lots of reasons to study train phenomena, already pointed out in [1]. We will rephrase some of them here and add our specific research subjects:

• From a physical-chemical point of view, there are two processes that govern train visibility an activation process which creates ionization and a decay process that destroys ionization. The amount of ionized atoms depends primarily on the energy or speed of the meteors. The decay of the train is mainly influenced by turbulent diffusion in the atmosphere. The relative influence of these two processes can be elucidated by a study of train percentages and durations for different showers as a function of meteor brightness.
• There are indications that there might be some differentiation in train percentages in a meteor stream as the Earth passes through filaments of different age. For example, the Perseids have already shown more trains in the maximum night than in the other nights [2]. Maybe this can also be seen in the past Leonid passages, having the problem that probably all observers didn't have time to mention train durations because of the high meteor frequency. Perhaps video observations can help here.
• Apart from meteor spectra, trains are the only probe of ionospheric conditions. It is very likely that the number or duration of meteor trains is dependent on the solar activity or other changing ionization events. Also the study of the upper atmosperic winds by observing long drifting trains can be valuable.
• It is known that different showers show different train percentages [3,4]. It is also clear that the speed is a primary factor, but not the only one. Maybe the population-index or other properties (such as composition) are important too.
• Then maybe there is a variation in train activities during the night. This would be the extension of the project. The observing form (see the section: "How to observe?") has also been adapted in this way. This would be the most challenging point of the project, and lots of observations are needed for this part. In [5], a type of long-enduring trains has been discussed, which occur only in the first half of the night and have a specific height. Maybe there are more (or longer) persistent trains in the first half of the night.
• Of course, other train material is also of interest, such as drawings or photographs from drifting trains or telescopic observations of trains.

Conclusion

We hope that a lot of observations will come to us in order to set up a database that will be used for the above mentioned investigations. The possible daily variation would only be recognized if many observations are combined. That is why we encourage meteor observers to take this little effort to send in the necessary information. Observations from the previous years can also be sent to us and would be very helpful.

More information about observing trains and submitting data using the meteor train observing form (originally composed by Mark Vints [6]), can be found in the "How to observe?" section.

References

[1] M. Vints, Meteor Trains, Proceedings IMC Potsdam, 1991.
[2] E. M. Moya, Spanish Perseid report 1983, WGN 13:4, 1985.
[3] R. L. R. Bellot, On the presence of trains in meteor showers, WGN 20:3, 1992.
[4] R. F. Hughes, Meteor Trains, Smiths. Contr. Astrophys. 3, 1959, p. 79.
[5] L. Kresak, On the Heights of Long-Enduring Noctilucent Meteor Trains, Bull. Astron. Inst. Czechoslov. 1, p. 56, 1949.
[6] M. Vints, Update on the Meteor train observing project, WGN 21:3, 1993.