Grazie della dritta, io sto cercando di tener duro con le osservazioni (che ho dovuto lasciar perdere per anni) ma non ho modo di leggere e tenermi aggiornato. Com'era facilmente prevedibile, il telelavoro con figlio a casa da scuola, corsi da trasferire online, piani di studio da riconfigurare e studenti che mandano 100 emails al giorno perche' vogliono il 6 politico e' molto peggio di prima.Vdellavecchia ha scritto: ↑23/03/2020, 7:48 Dal manuale online di WinJupos: "System II of Venus has a retrograde rotation of -85.7142857°/d [cioè pari a 4.2 g]and refers to the upper atmosphere visible in UV light. System I, on the other hand, is bound to the solid surface of Venus. Zero meridians of both Systems coincide at J2000 [all'equinozio del 2000] ".
Comunque ho trovato quest'articolo recente, di cui ho letto finora solo il "Plain language summary" con contributi dell'inossidabile Sanchez-Lavega e "images from amateur astronomers" (fondamentali, a quel che capisco, per colmare gli enormi gaps fra una sonda e l'altra).
Peralta, J., Iwagami, N., Sánchez‐Lavega, A., Lee, Y. J., Hueso, R., Narita, M., et al. ( 2019). Morphology and dynamics of Venus's middle clouds with Akatsuki/IR1. Geophysical Research Letters, 46, 2399– 2407. https://doi.org/10.1029/2018GL081670
Plain Language Summary
The atmosphere Venus is surprisingly fast with velocities 60 times faster than the solid globe of Venus. This atmospheric phenomenon is called superrotation and its mechanisms are yet unexplained for the scientists. The Japanese space mission Akatsuki from the Japan Aerospace Exploration Agency arrived at Venus in December 2015 to try to unveil this mystery. Among its instruments, the camera IR1 was prepared to observe the middle clouds of Venus (50–55 km over the surface), which are the most unknown and hardest to observe since they normally exhibit very low contrast in the images. Thanks to the images from the camera IR1, we have observed with high spatial resolution the middle clouds of Venus along the first year of observations of Akatsuki, discovering that they exhibit higher contrasts than expected and a wide variety of cloud patterns unrelated to what we observe at the top of the clouds (70 km above the surface). Finally, the motions of the middle clouds obtained through the combination of images from Akatsuki, amateur observers and the past mission Venus Express, have allowed to reconstruct a composite of the winds of Venus along 10 years, unveiling that the superrotation may be subject to long‐term variabilities unreported before