Astron. Astrophys. 342, L1-L4 (1999)

6. Conclusions

In this paper, we have outlined a new analysis of the the Tunguska event, starting from seismic data obtained by Ben-Menahem (1975) and improving the relationship between body speed, mechanical strength and airburst height. The main conclusion is that the Tunguska cosmic body was probably a stony asteroid, with a diameter of about 60 m.

We have also summarized the properties of the hypersonic flow around a small asteroid in the Earth's atmosphere. We have shown that the stagnation temperature is a direct measure of the body speed. This introduces a multiplicative factor of in the Eq. (1), which is instrumental to derive a reasonable solution for the Tunguska event. Eq. (6) is consistent with the idea that the meteoroid's fragmentation is due to the coupled action of thermodynamical and mechanical processes.

This kind of analysis can be applied whenever the body is large and compact enough to reach the lower atmosphere. Further investigations are needed for application to other cases. However, the crucial role of the stagnation temperature is probably a general feature of any realistic model of meteoroid flight and breakup.

© European Southern Observatory (ESO) 1999

Online publication: December 22, 1998
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