Schematic view of planetary material escaping through Venus magnetosheath flank. The red line and arrow show the region and direction of observations by BepiColombo when the escaping ions were observed. Credit: Thibaut Roger/Europlanet 2024 RI/Hadid et al.) BepiColombo mission to Venus has revealed surprising insights into how gases are stripped away from the upper layers of the planet’s atmosphere.
Unlike Earth, Venus does not generate an intrinsic magnetic field in its core. Nonetheless, a weak, comet-shaped ‘induced magnetosphere’ is created around the planet by the interaction of charged particles emitted by Sun with electrically charged particles in Venus’s upper atmosphere. Draped around the magnetosphere is a region called the ‘magnetosheath’ where the solar wind is slowed and heated.
“Characterising the loss of heavy ions and understanding the escape mechanisms at Venus is crucial to understand how the planet’s atmosphere has evolved and how it has lost all its water,” said Dominique Delcourt, researcher at LPP and the Principal Investigator of the MSA instrument. “This result shows the unique results that can come out of measurements made during planetary flybys, where the spacecraft may move through regions generally unreachable by orbiting spacecraft,” said Nicolas André, of the Institut de Recherche en Astrophysique et Planétologie and lead of the SPIDER service., and India’s Shukrayaan orbiter.