17 research outputs found
New studies of Venus
The American and Russian 1978 Venus explorations are reported. Highlights of their accomplishments and subjects of study are discussed. Included are investigations of the surface pressure, temperature, composition, and mass of the Venusian atmosphere, along with cloud layer structure, greenhouse effect, and diurnal variations
Three-dimensional modeling of lightning-induced electromagnetic pulses on Venus, Jupiter and Saturn
While lightning activity in Venus is still controversial, its existence in
Jupiter and Saturn was first detected by the Voyager missions and later on
confirmed by Cassini and New Horizons optical recordings in the case of
Jupiter, and recently by Cassini on Saturn in 2009. Based on a recently
developed 3D model we investigate the influence of lightning-emitted
electromagnetic pulses (EMP) on the upper atmosphere of Venus, Saturn and
Jupiter. We explore how different lightning properties such as total energy
released and orientation (vertical, horizontal, oblique) can produce
mesospheric transient optical emissions of different shapes, sizes and
intensities. Moreover, we show that the relatively strong background magnetic
field of Saturn can enhance the lightning-induced quasi-electrostatic and
inductive electric field components above 1000 km of altitude producing
stronger transient optical emissions that could be detected from orbital
probes
Infrared radiation of Venusian clouds
The thermal infrared emission of Venus measured by Venera-9 and Venera-10 is analyzed. The emission of the night side corresponds to a brightness temperature of 244 K. The brightest temperature of the day side is 233-234 K. The extent of the upper layer of clouds, in which the thermal emission is formed, is 4-6 km. The altitude of the emitting layer above the surface of the planet (64-67 km) is determined from the brightness temperature and the existing models of the atmosphere of Venus. In some cases, correlation is noted between the inhomogeneity and the details of the ultraviolet image. The day side temperatures strangely coincide with the freezing point of sulfuric acid at a concentration of 66-77%
Electrical discharges in the atmosphere of Venus
Data received from Venera 11 and 12 experiments involving the electrical activity of the atmosphere of Venus show that the electrical discharges occur in the cloud layer. Their energy is roughly the same as in terrestrial lightning, but with a pulse repetition frequency of the discharges which is much greater
Ultraviolet photometry of Venus: Scattering layer above the absorbing clouds
Experimental measurements by ultraviolet photometers aboard Venera-9 and -10 are presented, discussed, and compared with various theoretical models of the ultraviolet structure of the atmosphere of Venus. The model in best agreement with observation provides for a finely dispersed, 8 km thick Rayleigh scattering layer above the primary cloud cover. Dark contrast details are considered to be breaks or areas of lower optical thickness in the upper scattering layer