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Дата изменения: Wed Oct 29 20:34:35 2008 Дата индексирования: Tue Oct 2 11:18:52 2012 Кодировка: Windows-1251 Поисковые слова: meteor shower |
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"Результаты
исследований Венеры космическим аппаратом Венера-Экспресс" Д.В. Титов (Max-Planck Institute for Solar
System Research, Katlenburg-Lindau, Российской академии наук) Аннотация: More than 25
spacecraft from the Venus Express
continues and extends the investigations of earlier missions by providing
detailed monitoring of processes and phenomena in the atmosphere and
near-space environment of Venus. Radio, solar and stellar occultation,
together with thermal emission spectroscopy, sound the atmospheric structure
in the altitude range from 150 to Multi-spectral imaging
is performed to investigate the cloud morphology at different levels and its
latitudinal and temporal changes. Venus Monitoring Camera (VMC) shows
evidence of convection in the cloud layer at low latitudes. Streaky cloud
features indicate that the convection ceases in the middle and high
latitudes. Sequences of images are used to track motions of the cloud
features and to derive wind speeds in the 50- The chemistry and
dynamics of the mesopause region (~100 km altitude)
is being studied by observing non-LTE emission from O2 and NO
molecules in the UV and near-IR. This airglow peaks at the equator, close to
midnight and approximately at the mesopause level,
indicating a thermospheric solar-antisolar component in the atmospheric circulation. Composition
measurements over a wide range of altitudes are providing vertical profiles
of CO, H2O, HDO, HCl, HF, and SO2
in the mesosphere (70- The magnetometer (MAG)
and ASPERA (Analyser of Space Plasmas and Energetic
Atoms) measure the magnetic field and densities of neutral atoms, ions and
electrons in-situ. These
observations determine the structure and properties of the circumplanetary plasma and characterize escape processes
at Venus. They cover the time of solar minimum, and thus complement Pioneer
Venus investigations at solar maximum. Interestingly, the H/O ratio was found
to be ~2 thus suggesting that these ions are escaping in the stoichiometric ratio of water. The magnetometer is
detecting whistler signals in ~10% of the pericentre
passes. This is interpreted as evidence of lightning and the rate is estimated
to be at least as frequent as on Earth.
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