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Дата изменения: Tue May 18 17:48:07 2004
Дата индексирования: Tue Oct 2 05:02:17 2012
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Поисковые слова: южная атлантическая аномалия

Meteors in Planetary Atmospheres

A significant amount of effort was devoted to the question of the properties and observability of meteors in the atmospheres of Venus and Mars. This included the first investigation into the possibility of observable meteors in the atmosphere of Venus, such meteors being at least as bright as their counterparts on Earth. Although it would not be possible to observe these from the surface of that planet, owing to the perennial cloud cover surrounding Venus, it was established that they would be readily detectable from a spacecraft orbiting the planet. This work is now also in press.

The work on meteors in the atmosphere of Venus complements earlier work by Christou (Planetary & Space Science, 47, 1475, 1999) which investigated the possibility of meteor showers on Mars. In support of a longer term, more comprehensive investigation of the phenomenon, a collaboration has been initiated between Apostolos Christou and Jonathan McAuliffe (Armagh Observatory) and Christopher Trayner (University of Leeds), following a visit of the latter to Armagh in the autumn. The project is directed towards constructing an accurate thermophysical model of the meteor phenomenon. Combined with expectations of the meteoroid flux and speed, based on detailed numerical modelling of possible meteoroid stream orbits, it should then be possible to predict meteor properties such as brightness, duration and speed, characteristics which are particularly relevant to in situ spacecraft detection strategies.

Figure 4: Comparison of Mutual Events Data obtained from Armagh Observatory (red dots) and Nyrölä Observatory, Finland (green dots), on 15 March 2003. The Armagh results, obtained with a small-aperture telescope and a relatively cheap, commercially available imaging system, demonstrate the high fidelity of the Armagh data, the feasibility of observing phenomena of this type from the Armagh site, and the potential increase in data quality which can be expected, given a larger telescope (such as the newly restored 18-inch Calver reflector) and suitable upgrades in instrumentation. Time is shown in hours.