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Effects of the solar wind and the solar EUV flux on O⁺ escape rates from Venus

Fedorov, A.; Barabash, S.; Futaana, Y. +4 more

We investigate dependences of O⁺ escape rates from Venus both on the solar wind and the solar extreme ultraviolet (EUV) flux by using the 8.5-year dataset (May 2006 to December 2014) of the Ion Mass Analyzer and the magnetometer aboard Venus Express. We examine the O⁺ escape rates for 8 different conditions depending on the s…

Equatorial Kelvin-like waves on slowly rotating and/or small-sized spheres: Application to Venus and Titan

Yamamoto, Masaru

Equatorial Kelvin waves, which have been observed in planetary fluids, produce superrotation and climatological variability. Although the meridional flow component is zero on Earth's beta-plane in the absence of background basic flow, it cannot be neglected on spheres in some planetary fluids when the Lamb parameter is small. For a vertically prop…

The mean rotation rate of Venus from 29 years of Earth-based radar observations

Campbell, Donald B.; Margot, Jean-Luc; Nolan, Michael C. +7 more

We measured the length of the Venus sidereal day (LOD) from Earth-based radar observations collected from 1988 to 2017, using offsets in surface feature longitudes from a prediction based on a 243.0185d period derived from analysis of Magellan mission images over a 487-day interval. We derive a mean LOD over 29 years of 243.0212 ± 0.0006d. Our res…

Measurement of plasma channels in the Venus wake

Lundin, R.; Futaana, Y.; Zhang, T. L. +1 more

Plasma channels have been suggested to account for the observation of ionospheric holes in the Venus nightside ionosphere. They are produced by the erosion of the solar wind on the magnetic polar regions of the Venus ionosphere, and are related to a sharp plasma transition that extends along the flanks of the wake and that is located downstream fr…

Venus crater-related radar-dark parabolas and neighboring terrains: A comparison of 1-µm emissivity and microwave properties

Basilevsky, A. T.; Markiewicz, W. J.; Shalygin, E. V. +2 more

This work presents a comparative study of microwave properties and 1-µm emissivity for five Venus crater-associated radar-dark parabolas along with neighboring plains and some other geologic units. Craters of interest are Adivar, Bassi, Bathsheba, Sitwell, and du Chatelet with nearby crater Caccini having non-parabolic radar-dark halo. Micro…