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New Paper: Amateur Observers Witness the Return of Venus’ Cloud Discontinuity

The following paper is the result of a tedious task that my good friend Manos Kardasis undertook over the last two+ years. He noticed the presence of this (relatively newly discovered) feature in Venus and collected images from amateur observers worldwide to study in detail the discontinuity and constrain some of its properties by comparison with data from JAXA’s Akatsuki.

The importance of this work is twofold: a. it shows the high potential of observations with small telescopes to perform scientific studies of quality, and b. it promotes and encourage encourage amateur observers to perform and increase the observations of Venus.

I am really happy with this paper as it is a very well-deserved outcome of the work and effort that Manos put into this (fighting and joggling with many other things at the same time) and it showcases how a professional-amateur collaboration can succeed. Well done Manos!

Amateur Observers Witness the Return of Venus’ Cloud Discontinuity

Kardasis E., Peralta J., Maravelias G., Imai M., Wesley A., Olivetti T., Naryzhniy Y., Morrone L., Gallardo A., Calapai G., Camarena J., Casquinha P., Kananovich D., MacNeill N., Viladrich C., Takoudi A.

Firstly identified in images from JAXA’s orbiter Akatsuki, the cloud discontinuity of Venus is a planetary-scale phenomenon known to be recurrent since, at least, the 1980s. Interpreted as a new type of Kelvin wave, this disruption is associated to dramatic changes in the clouds’ opacity and distribution of aerosols, and it may constitute a critical piece for our understanding of the thermal balance and atmospheric circulation of Venus. Here, we report its reappearance on the dayside middle clouds four years after its last detection with Akatsuki/IR1, and for the first time, we characterize its main properties using exclusively near-infrared images from amateur observations. In agreement with previous reports, the discontinuity exhibited temporal variations in its zonal speed, orientation, length, and its effect over the clouds’ albedo during the 2019/2020 eastern elongation. Finally, a comparison with simultaneous observations by Akatsuki UVI and LIR confirmed that the discontinuity is not visible on the upper clouds’ albedo or thermal emission, while zonal speeds are slower than winds at the clouds’ top and faster than at the middle clouds, evidencing that this Kelvin wave might be transporting momentum up to upper clouds.

Figure 1: Observations of cloud discontinuities, observed in the 2019/2020 eastern elongation of Venus, showing different morphologies.

arXiv: 2202.12601
Journal: Atmosphere 2022, 13(2), 348

Hubble will see the Venus Transit

On June 5, 2012, Venus will pass in front of the Sun. This transit will follow numerous amateurs and professionals around the world, but it is interesting that HST will also participate in this! But how will they do it since Hubble cannot see directly the Sun? They will use instead a “mirror” and this mirror will be the Tycho crater in the Moon! Interesting …

(Credit: NASA, ESA, and A. Feild (STScI))

(Illustration Credit: NASA, ESA, and Z. Levay (STScI))